Types of Diamond
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The ancients believed that Agate rendered the wearer invisible and thus has been admired by humanity for thousands of years. It has found use in both practical and ornamental forms because of its beauty and durability. Agate is supposed to be a cooling stone as it reduces fever, quenches thirst, quiets the pulse and ensures good health. Agate is also believed to cure insomnia, ensure pleasant dreams, protect from danger, promote strength, healing and a bold heart. Wearers become temperate, continent and cautious. Formed in a unique way, the main conditions necessary for agate formation are the presence of silica from devitrified volcanic ash, water, manganese, iron and other mineral oxides that form the bands and inclusions. Agate is a fine-grained fibrous variety of Chalcedony Quartz and comes in many different forms ranging from transparent to opaque. Varieties include Blue, Blue Lace, Crazy Lace, Green, Indian, Moss, Tree and Wood. And the most popular forms are: Blue lace agate which has swirly white bands in a blue background; moss agate with its moss-like pattern; fire agate a brown-bodied stone containing yellow, green and orange spots, with an iridescent shimmer like opal. The value of the agate mainly depends on the variety of the agate. Most agates are in the low price range but some stones, carvings and unique pieces command higher prices. |
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Ametrine is actually two types of gems in one stone thus making it one of the world’s most unusual gem stone. The yellow-orange part of ametrine is citrine and the violet-purple part is amethyst. This unusual color variation is due to the presence of iron in different oxidation states within the crystalline structure. To highlight this color split the gem is cut into long shapes which is ideal for earrings and necklaces whereas larger gemstones make enchanting pendants, perfect for evening wear.Ametrine has been readily available to the consumer only since 1980 when material from the Anahi mine in Bolivia began to appear on the market, before which it was considered to be quite unusual and was known as: Amethyst-Citrine Quartz, Trystine or Golden Amethyst. Ametrine jewellery has increased in popularity since then and many jewellery designers are making full use of its unusual qualities today to produce some truly eye-catching items.
The astrological sign of Ametrine is Libra and is said to posses all the metaphysical properties of both Amethyst and Citrine combined, as well its own unique properties. Ametrine is said to aid in meditation, relieve tension, disperse negativity and help to eliminate prejudice. A fine split in the colors and the intensity of color are the most important aspects to consider when evaluating Ametrine gemstones. |
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The name Apatite comes from a Greek word meaning “to deceive”, as it has often been confused with more valuable gems such as Paraiba Tourmaline, Peridot & Beryl. Ironically Apatite is also the mineral that makes up the teeth & bones of all vertebrate animals.Though the mineral form of Apatite is quite common the gem quality specimens are rare. This combined with its softness (5 on the Moh’s Scale of Hardness) has prevented Apatite from becoming popular even though its existence has been known since ancient times.
A clear to opaque stone Apatite comes in many colors, including green, yellow, blue, violet and yellow-green. Cat’s Eye Apatite stones are also known. Apatite is found in: Brazil, Russia, Myanmar (Burma), Sri Lanka (Ceylon), Canada, East Africa, Sweden, Spain and Mexico. Apatite is best used in making earrings and pendants as it is quite soft and exhibits a pale translucency. Apatite is actually three different minerals depending on the predominance of either fluorine, chlorine or the hydroxyl group: Calcium (Fluoro, Chloro, Hydroxyl) Phosphate. These ions can freely substitute in the crystal lattice and all three are usually present in every specimen although some specimens have been close to 100% in one or the other. The cost of the stone depends on the intensity of the color. The best stones will be almost a neon greenish blue with clean clarity. Stones over 1 carat in size are rare and will command higher prices. |
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Axinite another rare and unusual gemstone is a “must have” among collectors. The name Axinite is from the Greek acine (meaning “axe”) for the axe-like shape of the original crystal formations. Primarily reddish brown, Axinite can also occur in yellow, yellow-orange, light blue, violet, gray and even black.
A series name for a group of four related minerals Axinite is composed of several different ions (Ca2 (Mn, Fe, Mg) Al2 (BO3OH)(SiO3) 4). Though all have the same structure they are different in terms of chemistry. They are named for their respective enrichment in iron, magnesium and manganese; or iron manganese intermediate – tinzenite. The minerals differ slightly in color and specific gravity. Ferro-Axinite is rich in iron and reddish brown to black in color with an average Specific Gravity of 3.31, while Magnesio-Axinite, is magnesium rich, pale blue to gray in color and has an average Specific Gravity of 3.18. Manganaxinite is manganese rich, yellow-orange in color, with a Specific Gravity of 3.32, while Tinzenite is iron and manganese intermediate, predominantly yellow, with a Specific Gravity of 3.37. Manganaxinite found at Franklin, New Jersey has an attractive yellow-orange color and a red fluorescence, a special characteristic that is not seen in the other Axinites. Despite the differences, most collectors refer to them as simply Axinite. Good specimens of Axinite can have an extraordinary color and crystal habit and a nice luster that make them popular for collectors. |
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Alexandrite is a form of the mineral Chrysoberyl and appears as cats eye or as a faceted gem with an unusual green tint. Discovered in 1830, Alexandrite appears medium to bluish green when seen under sunlight or fluorescent light and violet red when seen under candlelight or bright light. This property of color change is seen in many gemstones besides Alexandrite such as Sapphire, Garnet, Apatite, Tourmaline etc. However the extent of color change exhibited by the various gemstones varies and is the most extreme ever seen in natural gems. As these stones exhibit different colors under different lights they are best used in making earrings, which will exhibit the color change property of Alexandrite very distinctly. Since it is a hard stone, rings made of this gemstone are also very popular. Fine quality Alexandrite cats eyes are also used to make signet rings as these are semi-transparent with a distinct white eye. The major source of Alexandrite is found in the state of Minas Gerias, Brazil. In 1987, the largest deposit of Alexandrite was found at the Lavra de Hematita mine. And in 1993, another source was found near the Tanzania-Mozambique border. However the original Russian source is nearly depleted due to the popularity of this gemstone. The value of this gemstone mainly depends on the degree of the color change. The lower quality stone will exhibit a lesser change of color while retaining the original green color or may even appear brown under bright light. The evaluation of Alexandrite should thus be made in a dark room under a light source. |
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Similar to the present day Squid, Octopus and Nautilus, the Ammonites were Cephalopods, which could swim due to their unique shell construction, which was divided into air chambers. The air in these chambers allowed the animal to float and move around. Though Ammonite fossils are found in every continent, the ones found in Alberta, Canada are treasured since they exhibit the most vibrant colors. Some of them also display intricate patterns. Found in various sizes and colors, the value of Ammonites depends on its size, shape, color and overall appearance. And every Ammonite is unique in color and pattern; the rarest of which exhibits three or more colors and belongs to the AA grade. In Ammonites, the ones displaying one or more colors are graded as A, whereas the ones with indistinct colors are said to belong to the B grade. Ammonites have a Hardness of 5 – 6 on the Moh’s Scale, a Refractive Index of 1.52 – 1.67 and a Specific Gravity of 2.8. Mineralized fossils of Ammonite were found at St. Mary’s River in Alberta in 1908, by a member of the National Geological Survey team. However it was not until 1981 that good quality Ammonite was discovered, thus making it commercially viable. Thus in 1981 Ammonite was officially recognized as a gemstone by the International Commission of Colored Gemstones. The shell of the Ammonite was similar to the horns of the ancient Egyptian god of life and reproduction, thus it was named Ammon after this deity. Similarly the North American Blackfoot Tribe also know Ammonite as the Buffalo Stone, the stone that signifies wealth and abundance. The story has it that during a harsh winter, a famine hit the people. It is believed that the Great Goddess directed the Princess to find the brilliantly colored gemstone, which saw them through the harsh winter. Thus they believe it to be a gift from the gods. The Navajo tribesmen also used it as a healing stone. |
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Apophyllite is the name of a group of three minerals, which have similar chemical and physical properties. Of the three minerals namely Fluor-Apophyllite, Hydroxy-Apophyllite, and Natro-Apophyllite, the former is the most common and is also simply referred to as “Apophyllite”. It is the most colorful of the group and occurs in white, green, yellow, violet or colorless specimens. Some of them also fluoresce yellow or pale green under uv light. Apophyllite a very popular stone among mineral collectors is not well known among the public. It has a Hardness of 4.5 – 5.0 on Moh’s Scale and a Specific Gravity of 2.3 – 2.4. The name Apophyllite is derived from the Greek word, which means ‘to flake apart’ due to the reason that this crystal flakes when heated due to water loss. Hydroxy-Apophyllite is also known but they generally lack color. They are found at Ore Knob Mine, Jefferson, North Carolina. The rarest of the three Natro-Apophyllite is either yellow, brownish yellow, brown or colorless and is found in Okayama, Honshu, Japan. Apophyllite is quite popular among the collectors because of its beautiful colors, luster and crystal formation. The green form of Apophyllite especially is believed to bring about love and joy and beneficial in treating asthma, colon and bladder disorders. |
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Azurite has been named after the Arabic word ‘Azul’ which means blue. Named after its deep blue coloring, Azurite has also been used as a pigment for years. Used in the make-up of eyes by the ancient Egyptians, it is used in the manufacture of good quality artist’s paints even today. Azurite is chemically a Copper Carbonate Hydroxide Cu3(CO3)2(OH)2 compound and its intense coloring is due to the presence of copper, which is a coloring agent and the manner in which it combines with the carbonate groups (CO3) and hydroxyls (OH). Azurite alters chemically to form Malachite, which is green in color and the two varieties are found within one stone to create beautiful blue-green colored patterns. Not only do Malachite and Azurite occur together, they also have very similar formulae and thus Malachite can replace Azurite, so as to make a pseudomorph – an exact copy of an Azurite crystal except that it is green in color. Azurite mixed with dark red colored Cuprite also forms the rare mixture known as “Bluebird”. All three – Azurite, Azure-Malachite and Bluebird are used as gems. The demand for Azurite is very high as it is very popular among the collectors. The blue stone is cut into beads and cabochons and the larger masses are cut into ornamental pieces. Azure-Malachite too is cut into beads and cabochons. Azurite is brittle and transparent if present in thin crystals, otherwise the stone is translucent to opaque. It has a hardness of 3.5 – 4 on the Moh’s Scale and a specific gravity of 3.7+. As it is not very hard it can be easily scratched with a knife. The largest crystals till date have been found from Tsumeb, Namibia. Some of the great works made from this stone are also part of the collection in the Hermitage Museum, Moscow. Good fine quality specimens of Azurite are found in a number of places such as: Chessy (France), Laurium (Greece), the Black Forest (Germany), Cornwall (England), Burra Burra (South Australia), Broken Hill (New South Wales, Australia), San Carlos Mine (Mazapil, Zacatecas – Mexico) and in Utah, New Mexico, various places in Arizona and Bisbee, Cochise Co. (USA). Azurite-Malachite is sometimes coated with colorless wax or impregnated with hardening agents to improve its durability and appearance. Linarite stones are also mistakenly sold as Azurite as they both occur in the same locations and sometimes even resemble each other. However they can be distinguished on the basis of some physical properties. It is believed that Azurite clears the mind of its subconscious thoughts and helps people to understand their fears and desires better. Some also believe that wearing this mineral can make you more creative and enhance the intellectual receptivity. Others believe it to have medicinal value and use it to heal throat, spleen and spine disorders. And one of the most common uses of this mineral is in easing the rheumatic pain, maybe because of its close association with copper. |
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Amethyst a form of Quartz is one of the most common substances found on earth. Small amounts of iron and aluminum turn clear ordinary quartz into amethyst. Amethyst as well as other forms of quartz are piezoelectric thus they are widely used in important electronic applications. Amethyst has been popular as a gem since the Pre-Roman times. The intense color and easy availability of Amethyst has ensured its high popularity throughout the millennium. The Greeks believed that amethyst gemstones could prevent intoxication, while the medieval European soldiers wore amethyst amulets in battles for protection. The high-grade quality amethyst mined today mostly comes from Uruguay, Southern Brazil and Africa. Amethyst is available in colors ranging from pale to dark violet. The finest Amethysts have a medium dark violet coloration with a strong secondary red color. And darker shades of Amethyst may display slight color fluctuations under different light sources. All qualities of Amethyst are available in various different sizes and shapes. Though light grade Amethyst has a low price per carat, the finest quality stones are also very reasonably priced. Amethyst is ideal for all types of jewellery such as earrings, necklaces and rings and cut in a variety of shapes such as Antique, Baguette, Marquise, Octagon, Oval, Pear, Trilliant and some other fancy cuts in sizes ranging from a few points up to several carats. |
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Discovered in Spain, Andalusite is named after the province Andalusia. It is a polymorph with two other minerals, namely kyanite and sillimanite, with whom it shares the chemical nature but differs in its crystal structure. Andalusite which contains black / brown clay and / or carbonaceous material in its crystal inclusions arranged in regular symmetrical shapes, usually in the form of a cross of ‘X’ and is called “Chiastolite” Andalusite is pleochroic in nature that is it displays different colors when seen in different directions, Thus, it appears as a white, red, brown, orange and green colored stone. Though it is mined in Brazil and Sri Lanka, Andalusite is also found in Andalusia, Spain; Austria; California, USA and China. With a hardness of 7.5 on the Moh’s Scale and a Specific Gravity of 3.15 +, Andalusite has a vitreous luster and its crystals are transparent to translucent. It is also found in association with other minerals such as cordierite, biotite, feldspars, quartz, kyanite and sillimanite. While cutting Andalusite, the cutters try to orient the gemstone so as to get a pleasing mixture of colors namely, orangey brown, yellowish green and gold colors, thus exhibiting patterns of color dancing around its facets. Depending on the skills of the cutter, in rectangular variations one can see superior color play, whereas in round cuts the colors tend to blend together. It has been often referred to as a ‘poor man’s alexandrite’ because it offers color play at affordable prices. However one should remember that it features all the colors at the same time whereas alexandrite changes colors from green to red in different sources. Thus it is a gemstone that offers a lot of impact inexpensively. And is frequently used in men’s jewellery due to its color and durability. |
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Made of beryl, Aquamarine is a hard gemstone. For centuries it was believed to contain oceanic energy and thus was worn as amulets by sailors, who believed that the stone would give them power to overcome even the most powerful storm while at sea. Brazil was a major supplier of Aquamarines, but today African nations such as Nigeria and Madagascar also provide a great supply of this stone. It is a good choice for jewellery due to its hardness and is frequently worn as aquamarine rings. However due to its delicate color and clarity they are best when set in earrings and pendants. As aquamarines are eye-clean, any inclusions in this stone can be easily seen. Aquamarines are available in a variety of sizes and as the size of the stone increases, the color of the stone also tends to intensify. While evaluating this gemstone one should take into consideration the color intensity and the clarity of the stone. Deep blue colored Aquamarines are rare to find and therefore command higher prices in the gemstone market. However unlike other gemstones, people actually prefer much lighter, crystal clear gemstones to the richer, deeper colored ones. |
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A rare mineral Boracite was first discovered in Luneburg, Hanover, Germany in 1789. The mineral occurs in white to colorless as well as bluish, greenish, grey and yellowish colour.Formed from Magnesium Borate Chloride (Mg3B7O13Cl), the name Boracite comes from the fact that the mineral contains a high content of Boron. It ranks 7 – 7.5 on the Moh’s Scale of hardness and has a Specific Gravity of approximately 2.9 – 3.0. Crystals of Boracite are vitreous, transparent to translucent and occur in a variety of forms. It is also slightly soluble in water. Boracite is commonly found in marine evaporite environments, which provide the right factors needed for the mineral to form. Boracite is commonly found in association with other evaporite minerals like Anhydrite, Gypsum, Hilgardite, Magnesite and Halite. Its crystals are typically embedded in these other evaporite minerals or vice versa. Notable amount of Boracite is found in Yorkshire, England; Strassfurt, Germany; France; Bolivia; Chactaw Salt Dome, Louisiana and Otis, California, USA. A variety of Boracite found at Strassfurt, Germany is a fibrous form and is named Strassfurtite, after the locality. Boracite is easily identified by its crystal habit, color, associations, locality and its high hardness. In industrial applications, Boracite is used as an ore of boron for boric acid and borax (a cleaning agent and useful industrial chemical). Although it has nice color, clarity and the hardness necessary to be used as a gemstone, Boracite is rarely cut for this purpose, because it is slightly soluble in water and ordinary wear dulls its surface. Still, it is a very attractive mineral specimen among collectors.
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Beryl is colorless or yellow and is not known to many people. Beryl is a group of many beautiful and important gemstone varieties. But, it’s the different impurities that give the different varieties of Beryl their varied coloration. Beryl would be a very ordinary gemstone without these magnificent color varieties.
Among the many varieties of Beryl that are used as gemstones, the two most popular varieties are the green variety Emerald, and the transparent, blue-green variety Aquamarine. Others are Heliodor, a greenish-yellow variety; Morganite, a pink variety; and Goshenite, a colorless variety. Other varieties of beryl are simply called by their color, e.g: Red Beryl and Golden Beryl. Emerald is highly priced, and is one of the most valued gemstones. Its intense green color is incomparable to others. Beryl minerals are mostly composed of Beryllium Aluminum Silicate (Be3Al2(SiO3)6). It’s ranked 7.5-8 on the Moh’s Scale of Hardness with a Specific Gravity of approximately 2.6-2.9. Beryl is found in both translucent forms and transparent and usually has vitreous luster. Notable occurrences of Beryl include Colombia and some African localities for Emerald; Brazil, Russia and Pakistan for Aquamarine; California, Brazil, Africa, and many other localities for other variants. Beryl, collected as mineral specimen is worn as jewellery. |
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A lead carbonate (PbCO3), Cerussite is well known among collectors for its interesting crystal structure and fluorescence. The name Cerussite is derived from the Latin “Cerussa” which means “White Lead” in reference to its color, which is usually colorless or white; though it is also found in gray, yellow and even a blue-green color.Cerussite has a very high luster due to the lead content. Crystal twinning is common in Cerussite, a feature that makes it desirable for collectors. It can form geometrically intricate structures and shows a star shape because of multiple twinning.Another well-known characteristic of Cerussite is that it usually fluoresces cream-white to yellow in shortwave ultraviolet light. It is a relatively common mineral found in association with minerals like: Barite, Calcite, Anglasite and other secondary minerals. Its presence has been reported in Tsumeb, Nambia; Zaire; Morocco; Australia; Germany and Arizona, USA. Cerussite is used as minor ore of lead. It has a hardness of 3 to 3.5 on the Moh’s Scale of Hardness and a Specific Gravity of 6.5, which is very dense for a generally transparent mineral. Being rather soft, its specimens are very fragile and need to be handled with extreme care. Cerussite twinned crystals are highly sought after. The mineral is only occasionally faceted into gems for collectors. |
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Citrine a golden yellow form of quartz is one of the most affordable gemstones in the market. It derives its name from “citron”, the French word for lemon. It is believed to symbolize happiness, aid digestion, remove toxins from the body and be useful in the treatment of depression, constipation and diabetes.
In former times it was used as a protective talisman. Citrine is one of the accepted birthstones for November, as well as the anniversary gemstone for the 13th year of marriage. Found mainly in Brazil, Citrine appears naturally but most commercial form is the result of heating amethyst. Colors range from pale yellow to yellowish-brown and “Madeira” red (the color of wine). As Amethyst is heated to turn its color to gold colored Citrine, jewellery made from this stone should be kept away from prolonged exposure to strong light or heat. |
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Named after the location of its discovery – the Fluorite-Barite mine at Wagon Wheel Gap, Creed Quadrangle, Colorado, USA, Creedite occurs in attractive purple, white and colorless forms. It has also been found in Attica – Greece; Karaganda Oblast – Kazakhstan; Santa Eulalia – Mexico; Cape Province – South Africa; and Colquiri, Bolivia, New Mexico, Nevada, Colorado – USA.
Its crystals are found in a prismatic form and an acicular form in which a group of crystals radiate from a center. The latter form is so unique that it is highly sought after by collectors. It has been found in association with several minerals like Limonite, Cassiterite, Fluorite, Adamite and Vanadamite. When its color is purple, Creedite is easily confused with Adamite, though it is not as lustrous as Adamite. The Santa Eulalia locality in Mexico has produced the most beautiful specimens of Creedite; some of which have such a beautiful purple color with Quartz-like clarity that they were originally mistaken for Amethyst. Creedite is attractive and its crystal form is unique. As it is rarely found as a good size crystal, Creedite is only sometimes cut as a gemstone. It is believed to help in aligning the throat and crown charkas and is beneficial to the body’s cleansing system and useful for blood detoxification. |
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An extremely rare silicate mineral, Carletonite has been found in only one location so far, the mineral locality of Mt. Saint-Hilaire, Quebec in Canada. Identified by G Y Chao of the Department of Geology, Carleton University, Ottawa, Canada in 1971, the mineral was named after the name of the University.
Found in pale to deep blue and pink to colorless and white forms, the color zoning in Carletonite is either gradual or very sharp and irregular. Formed from Hydrated Potassium Sodium Calcium Carbonate Silicate Fluoride Hydroxide [KNa4Ca4(CO3)4Si8O18 (F, OH) – H2O], Carletonite has a hardness of 4.5 – 5 on the Moh’s Scale and a specific gravity of around 2.45. The crystals of Carletonite can be dull to vitreous and transparent to translucent. It belongs to the Apophyllite group of minerals, which also includes minerals like Fluorapophyllite, Hydroxyapophyllite and Natroapophyllite. The dark blue crystals of Carletonite exhibit the interesting property of ‘pleochroism’ in which the color of the crystal changes according to the angle it is viewed from. Thus Carletonite demonstrates a blue to pinkish-brown pleochroism. Though they are cut as gems, Carletonite crystals are mostly collected as rare mineral specimens. This mineral is also found in association with Pectolite, Albite, Arfvedsonite, Calcite, Fluorite and Apophyllite and at Mt Saint-Hilaire, as inclusions in Nepheline Syenite. |
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Charoite is one of the rarest minerals available in the market today. Discovered in 1976, till date it has only been found in the Murun Mountains in Yakutia, Aldan, Russia. Its name has been derived from the Charo River, from where this deposit has been mined. This region has a unique combination of physical and chemical conditions, which are needed for this mineral to form. Occurring in various shades of purple with white swirls, black patches and occasional golden dendrite formations (depending on the kind of impurity present), Charoite is a mineral composed of Hydrated Potassium Sodium Calcium Barium Strontium Silicate Hydroxide Fluoride [K(Na, Ca)11(Ba, Sr)Si18O46(OH, F)-nH2O]. It has a hardness of 5.0 on Moh’s Scale and a specific gravity of 2.5 – 2.8. Quite popular as an ornamental stone and as a gemstone, Charoite is ideal for beads, cabochons, spheres or in carvings and inlay work. Considered to be a healing stone, it is supposed to aid in the treatment of aches and pains, liver ailments, blood pressure and in enhancing self-esteem. Due to its appearance like purple marble and swirls, it cannot be mistaken for any other mineral. Thus this unusual look of Charoite is one of the reasons why it is so popular among the collectors.
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Due to the presence of cobalt the calcite is pink in color, which is further magnified due to the presence of calcium. Cobalt Calcite and Sphaerocobaltite both have identical crystals and occur in the same localities. Cobalt Calcite is found in the Danile mine in Neustadtel, Freiberg, Saxony, Germany; Ruashi, Shaba, Zaire; Boleo, Baja California, Mexico; and Zacatecas, Mexico. It has a hardness of 3.5 – 4 on Moh’s Scale and a specific gravity of 3.13. It is also commonly associated with Calcite, Dolomite and Malachite. With a hardness of 3.5 – 4, it is considered to be quite soft and thus the specimens are very fragile and should be handled with care. Thus it is best set in a pendant or as earrings. Of late its drusy variety with a nice sparkling screen is becoming quite popular among the jewellery designers. This pink colored gem is believed to help the heart, blood, the circulatory system, thymus glands and lungs.
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Cat’s Eyes are found in Myanmar, Brazil, China, Sri Lanka, and India. Those found in the Mogok mines in Myanmar and in Sri Lanka are considered the best. These localities produce the finest quality of Cat’s Eyes called “milk and honey”. When a flashlight is shined at the stone’s side it produces amazing color zoning. Half of the stone will appear milky white while the other half remains a honey color. The green form is considered the next best. Apart from its color, it’s value is judged by the brilliance of its luster, the sharpness of the eye, and its clarity and shape. |
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The most desired stones are brilliant yellows, greens and occasionally oranges. The brown Chrysoberyl is – the less valuable. Faceted stones over 10 carats are rare, over 20 carats extremely hard to obtain, and clean stones over 30 carats are museum pieces. It is said to bring in tranquillity, peace of mind and also increases self-confidence. Chrysoberyl also promotes kindness, generosity, benevolence, hope, optimism, renewal, new beginnings, compassion, forgiveness and resilient nature. Cat’s-eye Chrysoberyl is a translucent gem ranging in wide array of colors from a honey yellow or honey brown to yellowish green to an apple green. It is known for its reflected light effect called “chatoyancy.” This is achieved by cutting stones that have very small, parallel “silk” inclusions into cabochons. As the gem is rotated, a distinction is exhibited, silvery white line across its dome that seems to open and close like a cat’s eye. Unlike its high-priced cousin Alexandrite, regular Chrysoberyl is very reasonably priced and exceptionally hard (8.5 on the Moh’s Scale of Hardness), producing some extremely durable gems. Chrysoberyl is found all around the world including Brazil, Burma, India, Sri Lanka, Russia, and the Ural Mountains & Zimbabwe. The best cat’s-eyes also exhibit a “milk and honey effect,” when the stone is rotated, one side of the stone appears transparent, as the other side takes on a creamy appearance. In large cat’s-eyes, the milk and honey effect is an important consideration in valuing the stone. |
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This has been an important gem right from the royalty of Ur, the Mesopotamian capital of pre-biblical times, to Napoleon and Tibetan Buddhists; Cornelian has been revered for its healing, spiritual and creative qualities. It’s also known as Sadoine or Mecca Stone and sometimes spelt Cornelian, the name Cornelian is derived from Carne, the Latin for flesh, due to the stone’s coloring. A spiritual and religious stone, Cornelian was used by the Egyptian goddess Isis to protect the dead on their journey through the afterlife; it is the symbol of the Apostle Philip and was one of the stones on Aaron’s breast plate of judgment (Exodus: xxviii, 15-30). To this day Buddhists in China, India and Tibet believe in the protective powers of Cornelian and often follow the Egyptian practice of setting the stone with turquoise and lapis lazuli for enhanced power. Cornelian is recommended for those with bad memories, creative blocks, confused minds, weak voices and a lack of courage. Cornelian also helps hot-headed people overcome anger and establish self-control, and it even protects the wearer from envy and falling objects. It is said to be beneficial in treating impotence, infertility, insomnia, menstrual cramps, neuralgia, rheumatism, asthma, bad blood, lethargy and digestive problems. The red tints in Cornelian are caused by iron oxide impurities. It is most commonly made into beads, cabochons, and carvings. As Cornelian is fairly common, it is an inexpensive gem. The best Cornelian is translucent. Some Cornelian will be dyed. It’s often carved and the quality of carving is a key issue in determining a price of a Cornelian. |
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The hardest, rarest, densest natural substance known to man, Diamonds have been a source of fascination since 800 BC. In those days the Indians believed that diamonds were created when lightning struck rock and the sub-continent was the only producer of diamonds for an astounding 2,500 years. As bewitching as diamonds are they have produced more than their fair share of myths over the centuries.Diamonds were not cut until the 14th century and it wasn’t until 1725 that deposits were discovered in Brazil and 1866 that the South African storehouse was unearthed. While Africa is known as the Diamond continent, it is actually in Australia that the largest reserves are found – including the very rare and highly valued pink and red fancy colored diamonds. Diamonds are made of pure carbon atoms that exist deep in the ground, exposed to intense heat and pressure over billions of years. Over time, this pressure builds up and forces the diamonds and rocks up toward the surface in a volcanic-like explosion. The explosion creates a very deep, wide hole called a “kimberlite pipe” into which most of the diamonds settle. These “pipes” resemble gigantic carrots encrusted with diamonds. It can take years to fully excavate an entire pipe. Some amazing attributes of Diamonds are: Celebrated in song, diamond jewellery, has long reigned as the ultimate statement of ardor and affection and is found to be the most intimate of gifts. |
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These crystals of Calcium Boron Silicate (CaB2Si2O8) are mostly grayish and opaque, while some are clear and colorless or light pink. These rare gems are usually found in Mexico and the clear, colorless ones make the most attractive gemstones. As they have a hardness of 7 on Moh’s Scale, they make quite beautiful jewellery and an excellent alternative to Diamonds and harmonize with nearly everything. Found in locations such as Myanmar (Burma), Japan, Mexico, Switzerland, Germany and Danbury (Connecticut, USA), this mineral corresponds to the sun sign of Leo. It is believed to be an excellent healing tool, a powerful activator of the intellect and a mineral that helps remove toxins from the body. Though fine quality Danburites are clear or white, shades of pink, brown and yellow have been found with a clarity ranging from transparent to translucent. |
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Dolomite a common sedimentary mineral is named after a French mineralogist and geologist Deodat de Dolomieu (1750 -1801). Well known for its beautiful pink color, Dolomite is also found in other color shades such as white, yellow, gray, brown and black. The darker shades generally occur due to the presence of iron in the crystals.The Dolomite group of minerals include: Ankerite, Bensonite, Huntite, Kutnohorite, Minrecordite and Norsethite besides Dolomite, which is the most common mineral of the group. Formed from Calcium Magnesium Carbonate (CaMg (CO3) 2) Dolomite occurs in massive beds several hundred feet thick. Used as a source of magnesium in some cements, the hardness of Dolomite is 3.5 – 4 on Moh’s Scale and its Specific Gravity around 2.86.The crystals of Dolomite are transparent to translucent and pearly to vitreous in luster. This pearl like effect is best seen on the curved crystals. And it is the beautiful pink color and unique luster that makes Dolomite a very attractive mineral specimen among collectors. Though it is reported to be found from many places around the world, the well known sites where Dolomite is mined are the Midwestern quarries of the US, Ontario (Canada), Pamplona (Spain), Switzerland and Mexico. |
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A popular mineral among collectors, it occurs in white, brown, green and (rarely) orange, or gray. The name is derived from the Greek ‘Dateisthai’, which means “To Divide” referring to the fact that the mineral crumbles quite easily.Datolite takes form from Calcium Boron Silicate Hydroxide [CaBSiO4 (OH)]. It ranks 5 to 5.5 on the Moh’s Scale of Hardness with a Specific Gravity of 2.8 to 3.0. Datolite belongs to the Datolite/Gadolinite minerals group. Members of the group include: Datolite, Bakerite, Gadolinite, Hingganite, and a few other rare minerals. The minerals contain alternating borate and silicate that are connected to each other in a sheet like structure.Datolite occurs in two distinct forms: as discrete crystals and as massive nodules. The massive variety actually has a cauliflower-like surface; collectors for its beauty as a lapidary material value it. Massive Datolite, colored by copper and other minerals, is found in size of up to 10 inches in diameter. Such nodules range from white to red, reddish-brown, and orange, which is most valuable, and are usually cut as cabochons or sliced and polished for inlay-work. Pink Datolite is also widely known as “Sugar Stone”. First discovered in the Connecticut River valley, USA in 1806, some occurrence has been reported in Russia; the Lake Superior region of Michigan and Paterson, New Jersey, USA; Bancroft, Ontario, Canada; Charcas, Mexico; Schwarzwald, Germany, Africa and Norway. |
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While not used as a precious gemstone due to a lack of clarity, it displays a bright coloring and good hardness. Massive specimens are carved into cabochons, beads, sculptures, eggs and spheres and in China it has been used as a lapis lazuli imitation. While Dumortierite can be misidentified as other ornamental stones (i.e. sodalite, lazurite and lazulite), blue sodalite is less dense and has whiter portions, while lazurite and lazulite are not fibrous. Dumortierite occurs in Beaunan, France as well as Quartzite, La Paz County, Arizona; Colorado; Oreana, Nevada; New York, New York and Alpine, San Diego County and Los Angeles County, California, USA; Magadanskaya, Siberia, Russia; India and Sahatany, Madagascar. It has many associated minerals including quartz, kyanite, sillimanite, staurolite, andalusite, muscovite, lazulite and pyrophyllite. It’s a boro-silicate mineral, and is made unusual by its very attractive deep violet blue color. Interestingly, Dumortierite is the most common boro-silicate with the exception of the Tourmaline Group.
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Garnets are believed to contain both protective and destructive elements. The Crusaders set Garnets into their body armor, believing the protective power of the stones would lead them to safety. The name “Garnet” is believed to have derived from “pomegranate” with its red, “Garnet colored” seeds. While the name Garnet has long been associated with a rich red color, the gemstone actually comes in a much wider array of color variations including: reds, oranges, greens and color change. Garnets are found in a wide variety of locations including: Kenya, Sri Lanka, Thailand, Brazil, India & Arizona (USA), however the bulk of today’s Garnet supplies come from Africa. When evaluating Garnets, color is the most important characteristic. The color must be intense and uniform with a tone that is not too light or too dark. Fine Garnets should be eye clean with minimal inclusions under magnification. Size is also a very critical determinant of the stone’s value. Garnets are a group of related minerals, containing cubic crystalline structure with slight variations in their chemical compositions. In all, there are 7 major types of Garnets, which include Almandine, Pyrope, Spessartine, Grossular, Andradite, Rhodolite and Malaia. Andradite Garnets are undoubtedly one of the rarest gemstones. The intense medium green variety, known as Demantoid, is quite spectacular. Having the highest refractive index of all Garnets, Demantoid’s brilliance is second to none. |
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Ekanite is another of several minerals that occur in a beautiful green color. A beautiful green colored mineral, Ekanite is a radioactive, but non-hazardous, mineral composed of calcium sodium potassium thorium silicate (ThCa2Si8O20). It ranks 6 – 6.5 on the Moh’s hardness scale with a Refractive Index of 1.57 and a Specific Gravity of 3.3. Crystals of Ekanite are translucent and vitreous. Apart from the typical green, it also occurs in yellow and dark red colors. Ekanite specimens from Sri Lanka sometimes reveal a weak four-rayed star, but this phenomena is quite rare. The star form of Ekanite is considered one of the rarest gemstones available on the market today. In 1985 a beautiful 161.04 carat Ekanite cabochon displaying a unique eight-rayed star was found and cut in Sri Lanka. It is considered to be a one-of-a-kind specimen. Ekanite is also found in Mt St. Hilaire and Rouville Co., Quebec, Canada and at several locations in Siberia, Russia: Yakutia, Aldan Shield Torgo river basin, Davan and Murun massif. Ekanite is a very rare type that is not widely known to the general public. As rarer stones are more highly prized than more common varieties, Ekanite specimens can command quite high prices on the market; especially those with vivid green coloring and nice luster. |
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Besides the green color it is also found in other shades like: brownish green, black, yellow or gray. Composed of Calcium Aluminum Iron Silicate Hydroxide, [Ca2 (Al, Fe) 3(SiO4) 3(OH)], Epidote ranks 6 to 7 on the Moh’s Scale of Hardness with a Specific Gravity of 3.3 to 3.5. Found in vitreous and transparent or translucent forms, its crystals can be massive to radiating prismatic forms. Epidote is collected as a rare mineral specimen and the ones that are cut as gemstones are highly prized. This is due to the fact that despite its hardness and deep color, the crystals are rarely clear or large enough to facet and so it is not commonly cut and polished as a precious stone. The Green Monster Mountain in Alaska, which is privately owned and operated is one of the most interesting locations producing splendid crystal specimens of Epidote that are snapped up by private collectors and museums alike, the world over. Epidote is one of the birthstones for those born under the sign of Gemini. It is also noted for its ability of enhancing perception and intuition, supplementing personal power and increasing spirituality and spiritual growth. |
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Made of the base mineral beryl, Emerald has minute traces of chromium and vanadium, which gives this stone the “green fire”. This stone is so popular down the ages that one of the standard gemstone cuts is named after this stone.Emeralds have been dated back to more than 3000 years, during the period of the Ancient Egyptian Empire. Rings, earrings and bracelets have all been made, worn and sought since the ancient times. This “green fire” has been so highly valued in the European courts that story has it that the Spanish went on a bloody campaign to find the location of the Emerald mines in South America. This campaign ended in 1557 with the discovery of the Muzo and Chivor mines in present day Colombia.Emeralds of fine quality over one carat are rare to find. And those that are found may contain inclusions (known as “jardin” or the garden) that are visible to the eyes. The Colombian Emeralds are vivid green in color, whereas the ones found in Brazil are known for their varieties, with colors ranging from light green to dark green. As Emerald has a hardness of 8 on the Moh’s Scale, they are quite durable. However it is best if only professional jewelers clean them as ultrasonic and steam cleaning can damage the stone if not carried out properly. The value of Emeralds is highly dependent on its clarity, brightness and transparency. Very fine and good quality stone enables the viewer to see the back facet when seen from a face up position. The cut and the number of inclusions are responsible for the brightness of this gemstone. The purity of the green color adds to the beauty and value of the stone, which will be diminished due to the presence of yellow or blue overtones. |
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An unknown gemstone, Euclase is mainly favored by mineral collectors. While its color range is diverse and ranges from colorless to blue green, blue, yellow, light green colors, it is mainly found in sapphire blue and blue green shades. With a hardness of 7.5 on the Moh’s Scale and a specific gravity of 3.09 – 3.11, the crystals are found in transparent to translucent forms.It is found in granitic pegmatites alongwith other minerals such as topaz and beryl. And its crystal form, which can be easily mistaken for barite or celestite, aids in identifying this gemstone. Euclase that is weathered from its source and transported down stream is also found in alluvial gold deposits. Though clear gemstones of Euclase can be cut and set in jewellery, it is better known as a collectors’ item, with the crystals being prismatic with slanted terminating faces. Strong colored or large sized stones though very attractive are rare to find and much sought after by collectors.As Euclase is easily cleaved, gem cutters must display great care while working with this stone so as to avoid splitting an unfinished stone. And it is this reason that limits its acceptance as a common gemstone. As Euclase generally has a splotchy color distribution, this limits its appeal, though when a great colored well formed crystal is found it is highly valued. Euclase is mined in Ouro Preto and other areas within Minas Gerias (Brazil), Kenya, Zimbabwe, Tanzania, Ural Mountains (Russia), Germany and the famous emerald mines of Columbia. |
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A famous variety of Enstatite is Chrome-Enstatite, the emerald-green variety, which is commonly cut as a gemstone. Its beautiful green color is caused by traces of chromium, hence the varietal name. Usually composed of Magnesium Silicate (MgSiO3), Enstatite ranks 5.5 on the Moh’s Scale of Hardness, with a Specific Gravity of approximately 3.2. Its crystals are translucent to opaque and either vitreous or pearly in luster. Bronzite (also called Ferroan Enstatite) is another variety that can be found on the gemstone market. It occurs in greenish-black to brown. Bronzite often contains inclusions of highly reflective minerals, such as Hematite and Goethite, which give it a beautiful bronze-like effect when polished. Some polished specimens also exhibit a cat’s eye effect. Enstatite occurs in association with volcanic rocks and meteorites. Its occurrence has been reported worldwide including: India; Burma; Tanzania; the Tilly Foster Mine in Brewster, New York; Boulder, Colorado; Jackson Co., North Carolina; Lancaster Co., Pennsylvania and the Bare Hills in Maryland, USA.
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Eudialyte only occurs in alkali environments, especially sodium-rich ones. Its notable occurrences include: Mont Saint-Hilaire, Quebec, Canada; Julianehaab, Greenland; Madagascar and Magnet Cove, Arkansas, USA. However, most of the Eudialyte on the market today comes from the Kola Peninsula of Russia. Eudialyte is actually composed of several minerals: Sodium, Calcium, Cerium, Iron, Manganese, Zirconium, Silicon, Hydrogen and Chlorine [Na4(Ca,Ce,Fe, Mn)2ZrSi6O17(OH, Cl)2]. It ranks 5 to 5.5 on the Moh’s Scale of Hardness with a Specific Gravity of 2.9. Crystals of Eudialyte are vitreous and translucent to transparent. The Kola Peninsula in northwestern Russia is a region that has produced over three hundred different mineral species and is the type locality for over a hundred minerals. Eudialyte is an example of an unusual mineral that comes from these mineral unique sites. Not only is it rich in sodium, but has zirconium, cerium and often traces of yttrium in its structure. |
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Common Fluorite colors include: Purple, blue, green, yellow, colorless, brown, pink, black, reddish orange and more. Some of the most eye-catching examples are multi-color Fluorites with distinctive bands and zoning. The word “fluorescent” comes from the mineral Fluorite which commonly fluoresces blue and has been known to glow yellow, green, red, white or purple. Some Fluorites even display different colors under longwave and shortwave UV light. Chemically, Fluorite is Calcium Fluoride (CaF2) with a Hardness of 4 and a Specific Gravity of 3.0-3.3, and is available all around the world including: Brazil, Canada, China, England, Germany, Italy, Mexico, Norway, Russia, Switzerland, USA and more. As Fluorite comes in a variety of colors the worth of any piece is determined by an individual. Fluorite is highly sought after as it is a relatively soft stone with a glassy luster. Though gem quality specimens achieve greater prices than those favored by mineral collectors, it is an inexpensive stone; thus making it the second most popular mineral amongst collectors after quartz. |
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Garnets date back to the Bronze Age (i.e. more than 5,000 years ago), when it was a very popular gemstone. The name “Garnet” is believed to have derived from “pomegranate” with its red, Garnet colored seeds. Unlike other gemstones, Garnets are believed to contain both protective and destructive elements. Garnets are a group of related minerals, containing cubic crystalline structure with slight variations in their chemical compositions. In all, there are 7 major types of Garnets, which include Almandine, Pyrope, Spessartine, Grossular, Andradite, Rhodolite and Malaia. Though the different types of Garnets are made up of different chemical components they all share a Refractive Index of 1.72 – 1.94, Specific Gravity of 3.40 – 4.30 and Hardness of 6.5 – 7.5 on the Moh’s Scale. And are found around the world including: Kenya, Sri Lanka, Thailand, Brazil, India & Arizona (USA) in a wide range of warm colors such as reds, oranges, yellows and Burgundies, as well as greens and some rare color-change varieties. As Garnets display a wide variety of colors, color becomes the most important characteristic while evaluating these stones. The color must be intense and uniform with a tone that is not too light or too dark. Fine Garnets should be eye clean with minimal inclusions under magnification. Size is also a very critical determinant of the stone’s value. |
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The presence of Garnets can be dated back to the Bronze Age, which is more than 5000 years ago, when it was very popular. It is believed to have guided the Noah’s ark to salvation during the Great Flood, according to the Jewish and Christian mythologies. They are also believed to contain both protective and destructive power unlike other gemstones. Color plays a very important role in determining the value of Garnets. The color should not only be uniform but also have an intensity that is neither too light nor dark. Fine Garnets should be clean and have minimal inclusions. Size also is an important determinant of the stone’s value. Today the bulk of Garnet supply comes from Africa, though it is mined in various other places such as Kenya, Sri Lanka, Thailand, Brazil, India and Arizona (USA). |
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Available as a faceted gem, Goshenite has a refractive index of 1.57 – 1.60, a hardness of 7.5 – 8 on the Moh’s Scale and a hexagonal crystal system. Goshenite (Beryl) is famous for its perfect, six-sided hexagon crystal formation. All beryl varieties including Goshenite can be cut into various gem cuts. Though sometimes perfect, transparent crystals are worn as uncut necklace pendants. And though Goshenite is found in almost all beryl mines, they are especially found in North and South America, Northern Europe, East Africa, South Africa, Himalayan Asia and Colombia. |
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Beryl occurs in a variety of colors, but only the transparent ones are used as gemstones. As pure beryl is colorless, the traces of the different impurities are responsible for this gemstone’s vast color range. Heliodor has a hardness of 7.5 – 8, a refractive index of 1.57 – 1.60 and a hexagonal crystal system. They are available as both a faceted gem and as Heliodor Cats Eye. Beryl (Heliodor) is famous for its perfect, six-sided prismatic hexagon crystals that usually occur individually. Some well-crystallized 8-meter forms are also known to have existed. Treating the stone with oil can mask the internal flaws in Heliodor and thus one must be cautious of dealers who often apply this treatment to a stone without informing the buyer. All varieties of Beryl, including Heliodor can be faceted into various gem cuts. Some stones even display cat’s eye effect when cut and polished. Transparent beryl such as Morganite and Heliodor are also carved sometimes into ornamental figures. Perfect, transparent, six-sided rough Heliodor crystals are also worn occasionally as pendants. Heliodor is found in Madagascar, Brazil, Rangoon, Tien-Shan Mountains, Tajikistan, Middle Eastern countries, North Carolina and California in the U.S.
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Hemimorphite | |||||
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With its high Zinc concentration, Hemimorphite is also commonly used as a source of the minor ore of zinc. Hemimorphite has a hardness of 5 on the Moh’s scale and a Specific Gravity of 3.4. It is found in association with Hydrozincite, Limonite, Aurichalcite, Calcite and Smithsonite and occurs as veins and beds in calcareous rocks. Originally discovered in Romania, Hemimorphite is found in notable amounts in Santa Eulalia, Mapimi (Mexico), New Mexico, New Jersey (USA), England and Zambia. Hemimorphites are found in two distinct crystal forms. One form produces a blue to blue-green crust and the other form is a glassy, clear or white, thin crystal, which is prominently displayed in nearly all mineral museums around the world. Thus both the forms are a must in the collection of a serious mineral collector.
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Hauyne | |||||
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Hauyne is sometimes called Huaynite. It was discovered in 1807 on Mt Somma, among Vesuvian lavas, Italy by the French crystallographer, Mr. R. J. Hauy (1743-1822), and was named after him. The mineral has been found in a typically beautiful electric blue as well as green, red, yellow, and gray colors.It is formed from Sodium Calcium Aluminum Silicate Sulfate [(Na, Ca) 48Al6Si6(O, S) 24(SO4, Cl) 1-2]. It has a hardness of 5 – 6 on the Moh’s Scale with a Specific Gravity of 2.4 – 2.5. Its crystals are vitreous and can be sub-transparent to translucent, often occurring as well-formed coarse sized crystals. Hauyne belongs to the Sodalite mineral group.The Sodalite group is also a group within a group. Its members are also part of a larger group called the Feldspathoids, which are low-silica igneous minerals. Other members of the Sodalite group of minerals are Sodalite, Nosean, Lazurite and Hackmanite. As it is quite rare and has beautiful color, Hauyne is highly priced. Huayne naturally occurs in igneous rocks low in silica and rich in alkalies such as volcanic rocks, which provide the chemical supply and the environment needed for the mineral to form. Apart from Mt Somma, Italy, occurrences of Hauyne have also been reported in Tasmania, Australia, and in Eifel and Schwarzwald in Germany.
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Hiddenite | |||||
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Hiddenite is formed from Lithium Aluminum Silicate (LiAlSi2O6). It ranks 6.5 on the Moh’s Scale of Hardness with a Refractive Index of 1.66. The crystals are vitreous and can be in either transparent or translucent forms. For many years, occurrence of Hiddenite was limited to only North Carolina, however new desposits were recently discovered in Madagascar and Brazil. It is used as both a collecting specimen and as a gemstone. Due to its cleavage, splintery fracture and strong pleochroism, Hiddenite requires skill and expertise to cut and facet. The top and bottom of the crystal reveal the deepest colors and knowledgeable gem cutters take advantage of this effect to produce the finest quality Hiddenite. Hiddenite is one of two varieties of Spodumene. The other is Kunzite, a pink to lilac variety. Kunzite is the more common of the two and and is better known by most gemstone collectors. Kunzite has a lovely pink to lilac color that is unique in the gem kingdom. The green color of Hiddenite ranges from a yellowish to a bluish green. The gemstone is strongly pleochroic meaning that it can change color when viewed from different angles, thus a gem cutter must take care to orient the stone in the best position for the deepest color. |
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Indicolite a rarer form of Elbaite, has a typical color which is deeper than other blue gems, almost neon blue. Other varieties are: the green colored Verdellite, a cat’s eye variety, pink to red colored Rubellite and green and red colored (in the same stone) Watermelon Tourmaline. When viewed from different angles, all Elbaite specimens show stronger or even different colors. This property causes the blue color in Indicolite to appear darker when viewed down the axis of an uncut crystal. Thus to take full advantage of the color potential of the stone, the gem cutter must be aware of this property. Indicolite is a very good stone to be worn as it has a hardness of 7 to 7.5 on the Moh’s Scale. This gemstone mined in Madagascar, North America, Brazil, Myanmar, Africa, Siberia, Australia and Sri Lanka is now becoming very popular on the gemstone market due to its property of hardness. Indicolite’s blue color is believed to have a soothing power and relieve stress; those born in October also wear it as a birthstone. |
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Iolite, a transparent, violet-blue, light blue or yellow-gray mineral, shows many colors in a single stone. Due to its ability to help determine the direction of the sun on an overcast day, it is also known as ‘Vikings compass’. A popular gemstone, Iolite has a violet blue color, which has been compared to that of a light blue sapphire and so Iolite is also sometimes referred to as ‘water sapphire’.The color is attractive and popular and the gemstone quite affordable, thus making jewellery made from the Iolite stone quite popular in recent times. Besides using this stone in necklaces and earrings, they can also be set in rings as Iolite has a hardness of 7-7.5 on the Moh’s scale.
Pleochroism is very pronounced in Iolite and the colors seen while viewing the stone are violet blue, yellow gray and light blue. As the stone presents different colors when viewed from different angles, it is very important to look at the stone from several directions. If cut properly the stone will show its best blue color. Today the bulk of the stone comes from the mines of Sri Lanka, India, Madagascar and Burm |
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Jade was actually used by the Central American Mayan civilization hundreds of years before it attained a royal position in the Middle Kingdom. The Mayans mined jadeite in Guatemala making it into weapons and tools. The Chinese cult of Jade worship began in the Neolithic era when nephrite from the Kunlun Mountains was used in religious ceremonies, agriculture and war. The “Stone of Heaven” became so influential with the Chinese emperors that Confucius even wrote that men should aspire to its qualities of benevolence, intelligence, righteousness, humility, resonance, loyalty, faith, virtue and truth. Jade is harder than granite and is also very difficult to carve than solid steel. When diamonds were first introduced to China sometime between 1005 and 221 BC, they were originally more highly valued as jade carving tools than as gems. Although Jade has long been associated with the Chinese culture it wasn’t until l784 that Burmese jadeite found its way there and superseded the local nephrite as the imperial stone. The Maoris in New Zealand also used nephrite weapons. The fibrous structure of nephrite is very densely packed making it the “super skull crusher” gemstone. In spite of its low hardness, it is considered to be the toughest gem material. Jade is believed to bring good luck, health and fortune, assist during childbirth and protect infants from disease. Throughout Asia millions wear jade amulets believing that they give the owner power, knowledge, pure thoughts, long life and immortality. Intensity of color and transparency are the most important factors in judging quality. While jade is never fully transparent, the closer it gets to transparency, the higher it is valued. The most highly valued colors are the very rare “Imperial” green and apple green. Lavender jade is also very rare and attains high prices. A green swirl of jade in an otherwise white stone is known in Chinese as “moss in snow” and fetches princely sums. There are two distinct types of Jade – jadeite and nephrite. Nephrite is found in scattered areas around the globe and appears in a wide variety of colors. Jadeite predominantly comes from Burma and while it is available in gray, yellow, pink, blue, lavender, red, white, brown and black, it is most popular in the classic green that most people associate with the stone. |
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Discovered in 1902, Kunzite was named after G F Kunz, the chief gemologist of Tiffany’s and a noted mineralogist of the time. Known as the ‘evening stone’, Kunzite is the pink variety of Spodumene, while the green variety of the stone is known as Hiddenite. Kunzite exhibits pleochroism, that is there is quite a color variation when the crystal is seen either from the top or bottom. And because of its strong pleochroism, cleavage and splintery fracture, it is considered to be a real challenge to a gem cutter. However its lovely pink to violet color makes Kunzite a very attractive and desirable gemstone. As it is a pastel gem, it shows its color well in larger sizes. Made up of lithium aluminum silicate (LiAl (Si2O6)) the lithium in Kunzite’s chemical composition gives it the beautiful pink-violet color. As this stone can fade in high heat or direct sunlight, it is best worn in the evening – thus earning the nickname ‘Evening Stone’. The astrological signs for Kunzite are Scorpio, Taurus & Leo and this stone is believed to promote peace and purification and is considered excellent for meditation. A fragile stone with a hardness of 6 – 7 on the Moh’s scale this stone is mined in Afghanistan, Brazil, Burma, Canada, Madagascar, Malagasy Republic, Mexico, Pakistan, Russia, Sweden and the United States. |
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Depending on the angle at which the stone is being viewed, the colors of Kornerupine range from brown, colorless, green, greenish-yellow, pink to lavender. This stone claims the highest value when cut along its green axis orientation. Kornerupine is also found in cat’s eye stones. Found in Ratnapura – Sri Lanka, Betroka – Madagascar, Harts Range – Australia, Kenya and the Nuuk area of Greenland, the stone is formed from Magnesium Aluminum Iron Boro-silicate Hydroxide [Mg4(Al, Fe)6(Si, Al, B)5O21(OH). It ranks 6 – 7 on the Moh’s Scale of Hardness, has a Specific Gravity of 3.3 and the crystals range from transparent to translucent forms. It is suitable to make jewellery from this stone because of its hardness and is gaining popularity in the gemstone market. However due to its scarcity, it is considered to be a collectors stone. It is also said to help stabilize the emotional swings in patients suffering from depression. |
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Composed of Calcium Sodium Aluminum Silicate [Ca(50-70%) Na(50-30%) (Al, Si)AlSi2 O8], Labradorite has a Refractive Index of 1.55 – 1.75, Specific Gravity of 2.7 – 2.74 and a hardness of 6 – 6.5 on the Moh’s scale. Thus making Labradorite a versatile and wearable gem. Available in brilliant pastels and deep gold colors Labradorite makes for a truly outstanding gem, perfect for anytime the wearer wishes to brighten the mood. Transparent Labradorite is fine, clear and relatively free from inclusions. Shades vary from an almost lime-yellow color to bright canary yellows and golden tones. While looking at the gray-black colored form of the stone one must look for the intensity of schiller on the surface when viewed from different angles. Thus resulting in different colors being visible from different angles or a range of colors visible at the same time. Discovered in Labrador-Canada, Labradorite is also found in China and the Scandinavian Peninsula. |
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Composed of 10.81% Sodium, 1.48% Beryllium, 13.32% Aluminum, 23.76% Silicon, 0.76% Hydrogen, 43.62% Oxygen and 6.25% Fluoride, [Na6Be2Al2Si16O39(OH)2-1.5H2O], Leifite has a Specific Gravity of 2.6 and ranks 6 on the Moh’s Scale. The crystals of Leifite are transparent with a vitreous to silky luster and occur in various forms including fibrous, spherical aggregates and simple hexagonal prisms. Commonly associated with Aegirine, Arfvedsonite, Analcime, Calcite, Eudialyte, Serandite and other rare minerals, the occurrence of Leifite has been reported from: the Kola Peninsula (Russia), Narsarsuk (Greenland) and the mines of Mont Saint-Hilaire, Quebec (Canada). However the world’s finest and largest crystals have come from the locality of Mont Saint-Hilaire. The site of Mont Saint-Hilaire is truly unique as it has produced specimens of over three hundred different minerals and many more that are yet to be officially recognized. |
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Mellite Al2[C6(COO)6]•16(H2O), is a mellitate of alumina. It has a Refractive Index of 1.51 to 1.53 and has a hardness of 2.0 to 2.5 on the Moh’s Scale of Hardness. This mineral has been found in France (region of Seine), in Germany (Thüringen, Arten), in Hungary (Csordakut, Tatabanya, Sordakuit Banya) and in Russia (Malevka, Malowka, Tula) Found in deposits of brown coal its formation is partly the result of vegetable decomposition, a highly unusual situation amongst gemstones. |
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Beryl in its pure form is colorless or yellow and includes many important and beautiful gemstones like Emerald and Aquamarine. The different colors of Beryl arise from the mineral inclusions present in the stones and Beryl would have been a very ordinary gemstone had it not been for these colorful varieties. The pink variety Morganite has trace amounts of manganese in their crystal structure. Unfortunately, flawless specimens are extremely rare. Found in Madagascar, Brazil and in various parts of the US, the first material discovered displayed a bright purplish pink color that still sets the standard for the best Morganite in the world. Lower quality Morganite occurs in colors ranging from peach orange to pinkish yellow; though on heat treatment its color changes to a beautiful soft pink color. And if the stone is already pink then its color is enhanced because of this heat treatment. This heat treatment is stable and does not degrade Morganite under ultraviolet light. However there are people who collect the untreated Morganite over the treated pink form. Morganite is found in squat, tabular crystals closely resembling Rose Quartz but differing from it in the property of luster, wherein Morganite that is facetted in the correct way is much more lustrous than Rose Quartz. With a hardness of 7.5 to 8.0 on the Moh’s Scale this gemstone is actually tougher than its famous cousins. Morganite is suitable as a jewellery stone due to its luster, beautiful color and hardness, however its rareness has prevented this gem from gaining popularity. |
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An extremely rare mineral, Nuummit’s occurrence is limited exclusively to the Nuuk region of southwestern Greenland from where it gets its name. The area of Nuuk where Nuummit occurs is also called ‘Isuakasia’, the origin of which dates back almost four billion years. And apart from Nuummit, this area is also a source of other precious stones such as the beautiful Tugtupite and Greenlandite, which also happens to be the oldest precious stone in the world. As the ‘Isuakasia’ is situated close to the Inland Ice Cap, it is difficult to access this region and thus these minerals will never be available in large quantities.Used widely for centuries as beads and ornamental stones, Nuummit has only recently been named in the gemstone market. And have been designed into extremely attractive cabochons and miscellaneous shaped jewellery pieces.
Occurring in brown, golden brown, green and nearly black colors, Nuummit has a hardness of 5 – 6 and a Specific Gravity of 2.8. A foliated metamorphic rock, Nuummit is composed of Magnesium, Iron, Silicon, Oxygen and Hydrogen (Mg,Fe)7Si8O22(OH)2 and is approximately 3.8 billion years old, thus making it extremely unique. Nuummit also occurs in extremely small amounts in Spain and southwest of Douglas, Converse County, Wyoming, USA. |
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The official stones for those born in October are Opal and tourmaline. The physical structure of opal is unique. Tiny spheres of silicon dioxide form a pyramid shaped grid interspersed with water. Tiny natural faults in this grid cause the characteristic “play of color”. The effect is similar to the rainbow colors displayed on a soap bubble, only that this is even more dramatic. The combination of body color and play of color, we are faced with infinite possibilities. So, pricing becomes very crucial and is very complex. Size is also a factor with the carat price for larger stones accelerating accordingly. The intensity of the play of color and the extent to which it covers the opal’s surface also count. Opal is occasionally cut with pieces of matrix – the host rock. This strengthens the opal and can also lend a more interesting appearance. The finest examples are Boulder Opal, which sometimes have an undulating surface of “hills” and “valleys”. As opal is relatively soft and fragile it is often made into doublets or triplets – backed with plain black opal and fronted with clear quartz. These are ideal for opal rings or any piece that is likely to be receiving rough treatment. |
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The oldest known gem, Pearl was considered the most valuable stone for centuries and there have been plenty of legends surrounding it (Krishna’s wedding gift to his daughter, Cleopatra’s love potion etc.). The first known source of pearls was the Persian Gulf and the oldest known pearl jewellery is a necklace found in the sarcophagus of a Persian princess who died in 520 BC. This gem especially enamored the Romans. And it was believed that pearls were a symbol of the moon and had magical powers. The Chinese also used pearls to cure heart trouble, indigestion, fever, bleeding and eye ailments and till today use it as a skin whitener and as a cosmetic product. In India pearls were believed to give peace of mind and strength to the soul. Europeans too believed that whole or powdered pearls cured matters of the mind and heart. Generally worn as strings, pearl rings too are gaining popularity nowadays especially those with unusual black colored pearls. Queen Isabella funded Christopher Columbus’ expedition to discover the new world, which also led to the discovery of pearls in Central American waters. This led to a flood of American pearls in the European market. However greed for these sea gems resulted in the depletion of the American pearl oyster populations by the 17th Century. Then in 1919, a Japanese perfected and patented the art of cultivating pearls; thus turning production of pearls into an industry by itself. A Natural pearl or Oriental pearl forms, when an irritant enters into a particular species of mollusk. As a defense mechanism the mollusk secretes a fluid to cover this irritant. Layers of this coating, also known as nacre is deposited onto the irritant until a pearl is formed. A similar process is used to create a cultured pearl. However in this process the irritant is an artificially implanted mother-of-pearl bead or nuclei. As long as there are enough layers of nacre deposited on the nucleus to result in a beautiful pearl, the size of the nucleus is of little importance. Almost every pearl that is sold these days is cultured. And you are likely to come across “Natural” pearls only at auction houses. As they symbolize purity and innocence, pearls are considered as ideal wedding gifts. In the western hemisphere pearls are given as gifts to couples celebrating their 3rd and 30th wedding anniversaries. Saltwater pearls are more expensive than freshwater pearls. The Akova Japanese pearls are the most popular. However, freshwater pearls are available in a wider range of colors than saltwater, including purple, violet, orange, blue and gray. Freshwater pearls are cheaper to produce as each mollusk can yield up to 30 pearls. The American freshwater pearls are allowed to mature for longer periods as compared to other cultured pearls thus forming thicker nacre, which gives these pearls an unusually high luster. As pearls are available in a variety of colors, it is best to choose the color that complements you. While buying pearls check them under different light sources and make sure that the luster is uniform throughout the surface. Being porous they will soak up any substance that they will come in contact with, especially perfume, cosmetics and sweat, so make sure to wipe them clean after every use.
Petalite has been found in Brazil, Australia, Sweden, Finland, USA, Zimbabwe, Namibia and Elba in Italy. However Brazil and Namibia are the major sources of nice transparent stones. Composed of Lithium, Aluminium, Silicon and Oxygen (LiAlSi4O10), Petalite has a Specific Gravity of 2.4 and a relative hardness of 7 and is commonly found in Lithium-bearing pegmatite. A unique mineral, Petalite occurs in some beautiful pastel colors. The large sized stones are greatly desired by collectors due to its rarity. A stone that weighs above 2.0 carats is considered large especially in case of Petalite.
Prehnite an attractive mineral with a very good luster forms in the cavities of basaltic rocks and along fractures of diabase rock. With a bright luminescent green coloring Prehnite is a hydrous, calcium-aluminum-silicate mineral, which can be facetted or carved into ornaments. Usually found in a pale green to a grass green color, Prehnite can also be gray, white or colorless; some specimens even resemble jade. The first mineral to be named after a person – Dutch minerologist Colonel Hendrik von Prehn, Prehnite was discovered in Jurassic (Karoo) dolerite in the Cradock district of the Eastern Cape Province in the early 18th Century. A calcium aluminum silicate hydroxide: Ca2 Al2 Si3 O10(OH)2, Prehnite has a hardness of 6 – 6.5 and a Specific Gravity of 2.9+. It is found in India, South Africa, France, Germany, New Zealand, Switzerland, Scotland and in New Jersey, Connecticut, Virginia, Pennsylvania, California, Colorado, Michigan in the US. Believed to enhance one’s protective field and memory, Prehnite helps build the immune system and bring about peace and calm. Ideal for stress release, its color and unusual touch generates serenity and tranquility and is thus useful for curing anemia and blood disorders. It is also used as a Prediction stone by the Channellers and the Shaman’s.
An ocean blue variety of Pectolite was discovered in the Dominican Republic a few decades ago and was given the name Larimar, which is quite popular in the semi-precious stone market. Composed of NaCa2Si3O8(OH), Sodium Calcium Silicate Hydroxide, Pectolite, has a Specific Gravity of 2.7 – 2.9 and a hardness of 4.5 – 5 on the Moh’s Scale. The crystals are vitreous, transparent to translucent and occurs in fibrous tufts, globular masses and in radiating veins. Pectolite has been mined in Lake Country – California, Paterson and Franklin – New Jersey (USA), The Bahamas, Dominican Republic, Italy and England. Pectolite can be confused with other similar looking minerals such as Okenite, Wollastonite, Artinite and some others. But it can be easily identified due to its association with Zeolites, as others do not form this association and by the way it occurs in basalt cavities. Discovered in the nineteen seventies Larimar was named after the Dominican who had discovered the stone and is mined only on a unique Caribbean mountain and nowhere else in the world. It has an extraordinary blue color similar to that of the ocean in tropical areas. Larimar, the pale blue to sky blue variety of Pectrolite, is quite attractive and popular among those who like polished jewellery. Found in the Bahamas and Dominican Republic, Larimar is similar to Turquoise in appearance. And like Turquoise it too is used in contemporary Native American jewellery.
Heating certain types of quartz in the presence of iron forms Prasiolite. Prasiolite is sometimes confused with Green Beryl, Peridot (olivine) and Tourmaline, all gem types that are considerably more expensive than Prasiolite. Prasiolite has a Refractive Index of 1.55 and Specific Gravity of 2.65, with hardness of 7 on the Moh’s Scale. Most commercial Prasiolite is found in Brazil and Arizona (USA). The most important aspect to consider when purchasing Prasiolite is the Intensity of color and clarity. Color variations from a pale yellow-green to deeper, more lustrous greens are available. A tough stone displaying beautiful colors, Prasiolite is ideal for everyday wear and, as an inexpensive gem variety, is perfect for a wide variety of applications and usage. |
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The queen of the quartz, Amethyst is most expensive of the quartzes. Amethyst ranges from pale to dark violet. The finest qualities of Amethyst are a medium dark violet with a strong secondary red color. Darker shades of Amethyst may appear slightly differently under different light sources. Amethyst is available in all sizes and shapes. Light Amethyst will be very low in per carat prices with the finest qualities still well under US$l00 per carat. Darker Amethyst of any size will have color zoning. This may not be visible without extensive examination. Often the zoning consists of areas of red violet and areas of blue violet, this combination can enrich the appearance of the stone. Sometimes the zoning is easily visible and detracts from the beauty of the stone. The bi-color variety, Ametrine is part Amethyst colored and part Citrine colored. It was first discovered in Bolivia. Generally Ametrine is cut into octagon or emerald cut shapes to emphasize the two colors. Ametrine has been carved into some very interesting gem art works. Prices will start in the low end and go to moderate price per carat. The quartz without color, also called “rock crystal” simply lacks interest as a jewellery stone. Even when it is well cut it lacks brilliance. Occasionally it will contain some interesting inclusions that can increase its appeal. Colorless quartz is occasionally found with rutile needles inside, which look like long golden threads, sometimes arranged in a pattern. This is called Rutilated Quartz and is popular in art jewellery. Most gold bearing quartz is milky white rather than transparent. Smoky quartz is brown transparent quartz of all shades; it generally has a slightly grayish cast. Prices should always be very inexpensive. Quartz can be made into beads and have been popular for a hundred or so years; these are often faceted into appealing shapes. Tiger’s eye is quartz with asbestos inclusions; this gives it a subtle silky appearance. Generally it is golden to brown in color; it can also be dyed. Blue material is called Crocidolite. Star quartz is a fascinating stone; the quartz may be colorless or pink. The stars are six-rayed and roll around the stone as it is moved. |
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A manganese carbonate mineral (MnCO3), Rhodochrosite is a soft stone, ranking only 3.5 – 4 on the Moh’s Scale of Hardness and has a Specific Gravity of around 3.5. It is commonly found in association with Calcite, Quartz and metal sulfides. Rhodochrosite is found exclusively in the Sweet Home Mine in Alma and the Sunnyside Mine in Silverton, Colorado. And the Hotazel Mine in South Africa is famous for producing deep red clusters of Rhodochrosite crystals. However the mines most famous for producing Rhodochrosite are in the provinces of Catamarca and La Rioia in Argentina as they produce the most attractive pink and red-banded variety of Rhodochrosite, which are also occasionally referred to as ‘Inca Rose’ and used as an ornamental stone. Rhodochrosites are often used to make figurines and the tubular forms are often cut into circles with concentric bands, which are unique. Rhodochrosite jewellery is truly unique and beautiful due to its famous rose color. |
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The cementing material in sandstone is usually calcium carbonate, silica or iron oxide. As there are plenty of varieties of Sandstone available in the market, they are differentiated on the basis of their variations in color, hardness and texture, which in turn depends on the cementing material. Those which contain iron oxide are red to reddish brown in color, while those with silica or calcite as the binding material will be light in color, usually pale yellow, buff, or white. And green Sandstone in addition to sand and glauconite, often contains fossil shells and iron oxides. A common mineral found in the earth’s crust, Sandstone is available in large quantities in association with most other sedimentary rocks. Sandstone can be crushed to form loose sand grains, which can be then used in construction and in other industries as sand. Due to the variety of colors and textures sandstone is available in, it enjoys a place in the semi-precious stone market also. It is also used extensively in carvings and cut into spheres or oval forms. |
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Beautiful Blue Sapphires and multicolored Fancy Sapphires have long been found in Sri Lanka. However today Madagascar has actually out-stripped Sri Lanka in terms of volume. Yellow and gold sapphires are mainly sourced from Australia, Thailand, Sri Lanka and Tanzania. Green Sapphires are found in Australia and Thailand, whereas Violet Sapphires tend to undergo a color change, especially when viewed under daylight. Though these sapphires with a color change are not very well known they can be quite magnificent when set in gold. Though Sri Lanka provides a large portion of the world’s Blue Sapphires, Australia and Africa are the world’s largest suppliers of the same. Sapphires from the island of Sri Lanka are also known as “Ceylon Sapphires”. Exceptional Blue Sapphires are also sourced from Cambodia and Pailin. Burma too is known for their high quality supply of this stone. The most famous mining area for Fancy Sapphires is Sri Lanka. Here the pink-orange to red-orange variety of the gemstone also called Padparadsha Sapphire or “lotus blossom” is available. These are the most expensive of all the Fancy Sapphires and jewellery made with this stone is very popular. The popularity of Sapphires is mainly due to its easy availability in many different shapes, sizes and colors. Thus offering a great variety to gemstone lovers. Breakage of Sapphires rarely occurs due to the fact that the hardness of Sapphires is just below that of Diamonds, thus making it one of the toughest stones after diamonds. As these gemstones occur in a variety of shapes, colors and sizes, the intensity, uniformity and purity of color, the cut of the stone and the buyer’s preference are the most important factors in determining the value of these stones. |
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Today small amounts of Serandite are found on the island of Rouma, Los Archipelago, Guinea, as well as at the Gem Mine, San Benito County, California. However the quality and quantity from these locations can never compete with those found on the famous Mont Saint Hilaire site. Composed of Oxygen, Silicon, Manganese, Sodium, Calcium and Hydrogen (Na(Mn++,Ca)2Si3O8(OH), Serandite ranks 4.5 on Moh’s Scale of Hardness and has a Specific Gravity of 3.2 – 3.4. The manganese ions present cause the salmon pink coloration of Serandite. Occurring in prismatic crystals as well as in massive, compact forms, Serandite is found associated with other minerals such as Calcite, Analcime, Argirine, Vesuvianite and Grossular Garnet along with other extremely rare minerals found at Mont Saint Hilaire. The best-known association is the one of pink colored elongated Serandite with rounded snow-white Analcime crystals. Specimens of this association are really treasured by collectors. Serandite crystals with nice color and luster are also cut into attractive gemstones. |
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Smithsonite is the new name for Calamine. It was renamed after the founder of the Smithsonian Institution, James Smithson in 1832. The feature that sets it apart from the other gemstones is the fact that It has a very unusual luster, just like the glow of the melted wax under the candle flame.A Zinc Carbonate, Smithsonite is also known for its great color variations. This is due to the fact that Zinc is often replaced by other minerals, causing the color to vary. Addition of Copper renders the stone green to blue, cobalt results in a pink to purple color, whereas Cadmium is the reason for the yellow color of the Smithsonite stone. Although the most common are apple green to blue green colors, the lavender color stone is the most sought after. Other colors available are white, yellow, tan, brown, peach, red, blue and colorless.Smithsonite has various crystal habits, which include rounded rhombohedrons, scalenohedrons and a fascinating form called “botryoidal”. These radiating fibrous crystals appear like grapelike clusters. As Zinc is the main element in its chemical composition, Smithsonite was used as the principal source of Zinc till the 1880s. Today however it is being used to a much lesser degree in the advent of new alternating processes to form zinc. Formed in dry climates as a weathering product of Sulfide Zinc ores, the major sources of this stone include Namibia, Tsumeb and the Broken Hill Mine in Zambia. Other locations in South America and Europe and the Kelly Mine in Magdalena, New Mexico also produces some fine specimens. |
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Formed from Calcium Titanium Silicate (CaTiSiO5), Sphene has a Refractive Index of 1.84 – 2.11 and a Specific Gravity of 3.3 – 3.6. With a Hardness of 5 – 5.5 on the Moh’s Scale of Hardness, Shene is relatively brittle, thus care should be taken when set in rings. However due to its unique color shades it is ideal for earrings and pendants. Sphene is found worldwide in Mexico, Brazil, Canada, USA, Sri Lanka, Madagascar, Switzerland, Italy, Pakistan and Russia. The body color, the degree of inclusions and the cutting styles of the gem determines the dispersion of colors in the stone which in turn determines the value of the Sphene. Also clean stones larger than a few carats are rare. |
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A popular stone since the Bronze Age, Garnets are believed to contain both protective and destructive elements. It is also believed to be the gemstone that guided Noah’s ark to salvation during the Great Flood, according to both the Christian and Jewish mythologies. Due to its association with a rich red color, the name ‘Garnet’ is believed to have been derived from the red ‘Garnet colored’ seeds of the ‘pomegranate’. And though it is associated with the red color, it is actually found in a range of colors such as reds, oranges, greens and the color change varieties. Garnets are a group of 7 related minerals with slight variations in their chemical compositions. The major types are Almandine, Pyrope, Spessartine, Grossular, Andradite, Rhodolite and Malaia. Found in a variety of locations such as Kenya, Sri Lanka, Thailand, Brazil, India and Arizona (USA), the main supply today comes from Africa. . As Garnets are available in a range of different colors, color plays an important role in the evaluation of Garnets. The color of the stone should be intense and uniform and should suit the wearer’s personality. Size too is an important determinant of its value.
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Tanzanite has a hardness of 6 – 7 on the Moh’s scale, thus ultrasonic should never be used to clean this gemstone, as it is quite fragile. However there are Tanzanite rings, earrings and necklaces that are available in the market that enhance the personality of the wearer. Zoisite, the greenish to brownish color mineral when heated to 600 degrees Celsius, undergoes an amazing metamorphosis, resulting in this vibrant blue to blue violet gemstone – Tanzanite. Though initially only small stones were available, today larger stones are also seen in the market. The value of these stones mainly depends on the color of these gemstones, which display an amazing blue during daytime and a violet shade under bright light. Thus the gemstone, which has the minimum violet color even when viewed under bright light commands a high value. Since flawless Tanzanite crystals are easily found, the stone should not contain many inclusions. |
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Composed of calcium magnesium iron silicate hydroxide [Ca2 (Mg, Fe) 5Si8O22(OH) 2], a pure form of Tremolite without any iron impurity has a creamy white color. The iron content in the stone will increase the specific gravity and the index of refraction and will also darken the color of the stone. Tremolites are also known to exist in different forms such as: a chromium containing deep green colored variety known as Chrome-Tremolite, a pink to lilac colored variety – Hexagonite and a fibrous Mountain Leather or Mountain Cork Tremolite which has an appearance of a cloth. The mineral has also been found in other locations such as the area around Wilberforce, Ontario – Canada; De Kalb, St Lawrence Co., New York; California; Arizona and Canaan, Connecticut – USA; Tyrol and Piemonte – Italy; Tremola Valley – Switzerland; Tanzania and Finland. With a hardness of 5 – 6 on the Moh’s Scale and a Specific Gravity of 2.9 – 3.1, Tremolite specimens are translucent to transparent and can be perfectly clear. Thus due to its property of hardness and luster it is used as a stone in making jewellery. |
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Turquoise has always been highly valued right from the ancient times by the Egyptians, Persians, Mongols and Tibetans. As Persians had a preference for sky blue colored Turquoise the term “Persian Turquoise” was coined; however this term is now used as a color grade indicator and not as a geographical indicator. The interest of the Europeans in Turquoise can be dated back to 500 BC; however there was no impact of this stone on the European fashion scene until the latter part of the middle ages. The name Turquoise is supposed to be derived from the French word pierre turquois meaning Turkish stone as the Europeans believed that the stone had come from Turkey. When actually it had been mined from the Sinai Peninsula or Alimersai Mountain in Persia around 5000 BC. The national gemstone of Iran (then Persia) has always been the Turquoise, which means victorious – “Ferozah” in the Persian language. There was a huge demand for Turquoise during the beginning of the first Millennium AD when both the Chinese and the Native Americans were fascinated by the blue colored stone. The Chinese imported most of their stones from the Persians, Turks, Mongols and the Tibetans even though they had some mines in their empire. The Aztecs in Mexico mined Turquoise between 900 – 1000 AD; whereas the Anasazi people mined Turquoise in Arizona, New Mexico and Colorado. Turquoise from the city of Chaco Canyon found its way to the American continent and had also been unearthed from the great Mayan city of Chichén Itzá in the Yucatán. By the 16th century, the American Southwest societies were using Turquoise as a currency. The Native American culture especially uses Turquoise in Navajo concha belts, Zuni bracelets, thunderbird motifs and squash blossom necklaces. This Indian style or Native American Jewellery with Turquoise mounted in silver is a new trend among designers. Prior to this, the Native Americans – the Navajo craftsmen made solid Turquoise beads, carvings and inlaid mosaics. However most of the Turquoise and Silver jewellery and ornaments, belts sold today in the US are made in China and Thailand as it is relatively cheaper in those countries. Turquoise a hydrous phosphate of aluminum and copper CuO.3Al2O3.2P2O5.9H2O Hydrated Copper Aluminum Phosphate, has a Hardness of 5 – 6, a Specific Gravity of 2.6 – 2.8 and a Refractive Index of 1.61 – 1.65. This birthstone for the month of December is always an opaque gem but translucent stones though rare are known to exist. Turquoise is believed to help one in new projects, warn the wearer of danger by changing color and bring happiness and good fortune to all. Many ancient cultures believed that the blue of Turquoise was supposed to have powerful metaphysical properties. The treasure of Montezuma displayed in the British Museum, consists of a carved serpent covered by a mosaic of Turquoise. In ancient times in Mexico, the use of Turquoise was reserved for the gods. The Asians believed that this stone could protect them from all evil. Whereas the Tibetans carved it into their ritual objects and wear it as part of their traditional jewellery. Thought to promote prosperity, the ancient manuscripts of Persia, Afghanistan and Arabia spoke about how the change in color of Turquoise determined the health of the person. Turquoise rings are given as forget-me-not gifts in Europe even today. And the gemstones form Iran are said to be the best due to their clear sky blue coloration with no green color or black veins see in it. The bluer the blue the higher is the value of the stone. Since it is porous it should be kept away from chemicals and cleaned only with warm soapy water. |
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The presence of Topaz can be dated back to the Ancient Egyptian Empire. The popularity of this stone grew tremendously during the Middle Ages, when it was believed to contain the power to strengthen the mind. This sparkling gemstone has been used to create some amazing pieces of Topaz jewellery.Many referred to Topaz as a yellow to orange gemstone in the past but today due to a large supply of blue Topaz in the world market, many believe that Topaz is exclusively a blue gemstone. However in reality Topaz occurs in a wide variety of colors and even exhibits some unusual effects as seen in smoky topaz. The name Topaz is derived from the Sanskrit word ‘tapas’.Found in a variety of shapes, sizes and colors, Topaz is ideal for usage in a wide variety of applications. Though Brazil is the world’s largest supplier of Topaz, Russia and Pakistan are also emerging as new sources of Topaz. The colors, which are rare and most desirable by gem collectors, are red and intense pink. Gems with these colors fetch a higher price. Also Imperial Topaz or bright orange colored Topaz fall in the moderate price range whereas the blue colored Topaz are priced lower than the rest and are very popular because of the color shades, sizes and shapes they are available in. While determining the value of this stone one should take into consideration the intensity of the color and the clarity of the stone as well as the color preference of the wearer. |
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A green variety of grossular garnet (Ca3Al2(SiO4)3), Tsavorite gets its coloring from vanadium and / or chromium impurities. It has a hardness of 7 – 7.5 on the Moh’s Scale, Specific Gravity of 3.6 – 3.68 and a Refractive Index of 1.74, thus making Tsavorite a suitable gem for all types of jewellery. Tsavorite occurs in colors ranging from light green to very dark shades of green. The finest stones have an intense medium green color and are eye clean. And as more supplies have reached the world market, their popularity has been increasing over the years. While evaluating this stone it is important to take into consideration the color of the stone, which should be uniform and intense, with a tone that is not too light or too dark. The gemstones must be eye clean with minimal inclusions seen under magnification. Size too is an important determinant while evaluating the stone’s value. |
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Some tourmaline crystals may appear as crystallized rainbows with several bands of color, ranging from the most brilliant red to the deepest blue. Many refer to tourmaline as the “muses’ stone”, for they believe that its imaginative colors contain inspirational powers which enable the mind of its beholder to bring forth limitless profound vision. It has a hardness of 7-7.5. This multitudinous gem is ideal for all types of jewellery setting. Tourmaline earrings, tourmaline necklaces, tourmaline rings and other types of tourmaline jewellery are all well-suited to everyday wear and with its relatively affordable price and the variety of colors. The intensity of color and the clarity of the gemstone are the most important considerations. Green chrome and Paraiba tourmalines are the most expensive color varieties, due to their spectacular beauty and rarity. Tourmaline is found in various colors, the most common being green and pink. The red variety is often referred to as “rubellite”, as its vibrant red color often resembles that of the finest rubies. A rare green chrome variety of tourmaline found in Tanzania is also available, but in small quantities. An extremely rare variety is the Paraiba tourmaline. Found in Brazil, this gemstone exhibits very intense neon-like blue and blue-green colors. It is common to find bi-color and multi-colors tourmaline with visible inclusions.
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Nepheline – Syenite, a medium to coarse grained, light to medium gray colored igneous rock is predominantly composed of a silicate mineral called orthoclase (KAlSi3O8). Minerals that are found in Nepheline – Syenite generally occur embedded in massive sodalite or may be in small randomly distributed, irregular shaped cavities not more than 1 cm in dimension. Xenoliths occur in Nepheline – Syenite which are fine-grained, dense, dark gray to brownish gray and are significantly different from most Nepheline – Syenite found, in terms of their appearance and texture. Sodalite xenoliths have so far produced the largest number of minerals in the growing list of minerals in recent times. Villiaumite is one such mineral found and added to the list. Villiaumite occurs in colors ranging from pale orange-red to very deep carmine red. With hardness similar to that of an average fingernail that is 2 – 2.5 on the Moh’s Scale and a Specific Gravity of 2.8, Villiaumite is transparent and has a glassy luster. Composed of approximately 54.75% of Sodium and 45.25% of Fluoride (NaF, Sodium Fluorine), Villiaumite has anhedral to subhedral crystal structure. Commonly associated with Amphiboles, Calcite, Eudialyte, Fluorite, Nepheline, Pectolite and various other minerals from the sodalite xenolith environments, Villiaumite can be easily distinguished from other minerals because of their color and crystal forming habit. |
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The two major suppliers of Zircon are Thailand and Cambodia, apart from Vietnam, Burma, Sri Lanka and Africa that supply these marvelous gemstones to the world market. There are three natural types of zircons: low, medium and high. The variance is due mainly to the differences in the specific gravity and refractive index. Having the highest refractive index among any natural gemstones, with the exception of diamonds, the brilliance of high zircon is second to none. Its refractive index is purely dependent on the temperature. Despite its brilliance, Zircon is quite brittle and can easily be chipped or scratched. A unique characteristic of zircon is that the light splits into two rays as it passes through the stone. As a result, the back facets appear as double images. They are often blue or colorless. Some of the other color varieties are yellow, orange, green, and brown. The intensity of color and clarity is the most important criteria and any presence of flaws diminishes its value. |