Gemstone Chart |
Natural Oligoclase Oligoclase is a rock-forming mineral belonging to the plagioclase feldspars. Oligoclase is famous for its two gem varieties: Sunstone and Moonstone. Color: green, orange, red, colorless Categories: semi-precious stone Chemical Composition: [Na,Ca]AlSi3O8 Crystal Group: Triclinic Refractive Index: 1.53 - 1.54 Hardness: 6 - 6.5 Density: 2.62 - 2.65 Occurrence: Tvedestrand and Hitero on the south coast of Norway; near Lake Baikal Russia; Ontario, Canada; Tanzania; Kangayam, southern India; France; and in Maine, New Mexico, New York, North Carolina, Pennsylvania, Virginia and Oregon in the USA.
| Natural Opal Opal is the most colorful of all gems. It is a form of silica chemically similar to quartz, but more like glass and containing a variable amount of water within the mineral structure. Its splendid play of color is unsurpassed, and fine examples can be more valuable than diamond. Precious opals (black and white) are cut and polished into cabochons and used in all forms of jewelry. Color: White, green, blue, black, red, orange, violet, pink, grey, yellow. Categories: precious stone Chemical Composition: SIO2nH2O Crystal Group: Amorphous Refractive Index: 1.44-1.46 Hardness: 5.5 - 6.0 Density: 2.65 - 3.00 Occurrence: Czechoslovakia, Mexico, Honduras, Australia, Brazil, Tanzania.
| Natural Pezzottaite Pezzottaite is a raspberry-red to pink member of the Beryl Group named after Dr. Federico Pezzotta. Discovered in Madagascar and IMA approved in 2003. It is one of the great new gem discoveries of the last 20 years. Categories: semi-precious stone Crystal Group: Trigonal Refractive Index: 1.604 - 1.615 Density: 3.1 Occurrence: Madagascar, Afghanistan
| Natural Rhodochrosite Rhodochrosite is a manganese carbonate mineral with chemical composition MnCO3. The pink color of rhodochrosite is caused by the element manganese and it is formed when manganese is dissolved by ground water and combines with a carbonate material and then drips off the ceiling of caves and crevices deep underground.Rhodochrosite often forms pink and white bands. It is often carved into figurines or boxes while the tubular stalactite formations are often sliced for use in jewelry. Fine gem quality crystals are sometimes cut into gemstones for use in high end jewelry, but the more common grade is used extensively in silver and gold jewelry. Color: Rose red, raspberry red, pink, grey, fawn, brown Categories: semi-precious stone Chemical Composition: MnCO3 Crystal Group: Trigonal Refractive Index: 1.600 ¨C 1.820 Hardness: 4 Density: 3.45 ¨C 3.70 Occurrence: Argentina; Colorado, U.S.A.; Romania; Hungary; India; South Africa; Saxony, Chile; Peru; Mexico.
| Natural Rhodolite Rhodolite is a beautiful pink to violetish red garnet which was named after the rhododendron flower. Commercially rhodolite is one of the most important garnets. Rhodolite is quite available in small sizes which are relatively low in price. Very fine large rhodolite garnets are rare and are moderate in price. Color: red, purple-red Categories: semi-precious stone Chemical Composition: Al2(SiO4)3 Crystal Group: Cubic Refractive Index: 1.75 - 1.77 Hardness: 7.25 Density: 3.74 - 3.94 Occurrence: Brazil, East Africa, Ceylon, India, Madagascar, Zimbabwe
| Natural Rubelite The rubellite is a particularly beautiful gemstone from the colourful family of the tourmalines. Its colour shines in the most beautiful nuances from red to shocking pink. Rubelite is rich in lithium and free of magnesium and iron. Color: Hot Pink to Intense red Categories: semi-precious stone Chemical Composition: (NaCa)(LI,MgFe,Al)9B3Si6(O,OH)31 Crystal Group: Hexagonal Refractive Index: 1.624(+.005, -.005) - 1.644(+.006, -.006) Hardness: 7-7.5 Density: 3.06 (.05, +.15) Occurrence: Brazil, Madagascar, Nigeria, U.S.A.
| Natural Ruby ruby is a pink to blood-red gemstone, a variety of the mineral corundum.Ruby has been the world's most valued gemstone for thousands of years. It was said to be the most precious of the twelve stones God created when he created all things and this "lord of gems" was placed on Aaron's neck by God's command. Color: red, orangey red, violetish red Categories: precious stone Chemical Composition: AL2O3 Crystal Group: Hexagonal Refractive Index: 1.759-1.778 Hardness: 9 Density: 4 Occurrence: Burma, Thailand, East Africa, Vietnam, Madagascar.
| Natural Sapphire Sapphire is a gemstone variety of the mineral corundum,Blue is the main colour of the sapphire. Its beauty, its magnificent colours, its transparency, but also its constancy and durability are qualities associated with this gemstone by gemstone lovers and specialists alike.Fancy sapphires are pure individualism and are just made for lovers of individualistic coloured stone jewellery. They are currently available in a positively enchanting variety of designs - as ring stones, necklace pendants or ear jewellery. Color: blue, bluish purple, bluish violet, greenish yellow, orangy yellow, purple, red, reddish orange, red-orange or orange-red, reddish purple, red-purple or purple-red, slightly purplish red, violet, violetish blue, yellow, yellowish orange, pink Categories: precious stone Chemical Composition: AL22O3 Crystal Group: Hexagonal Refractive Index: 1.759-1.778 Hardness: 9 Density: 4 Occurrence: Sri Lanka, Burma, India, Kenya, Tanzania, Madagascar, Thailand, U.S.A., China
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