Gemstone Chart |
Natural Freshwater Pearl Freshwater pearls are a kind of pearl that comes from freshwater mussels.Freshwater pearls come in many shapes from round to button shapes, from flat flakes to rice shapes and in many colors. As with the salt water Akoya pearl the round shapes are generally more expensive. Color: orange, pink, white, gray, light purple, rose, black, brown, gold, yellow, silvery, green, blue, bronze. Categories: semi-precious stone Chemical Composition: CaCO3 Crystal Group: Not applicable Hardness: 3.5 - 4.0 Density: 2.66 ¨C 2.78+ Occurrence: China, Japan
| Natural Grossularite A member of the garnet group, grossularite is found in a variety of colors including, yellow, brown, white, colorless, green, violet-red, and orangey red. Color: Brown, yellow, green Categories: semi-precious stone Chemical Composition: Ca3Al2(SiO4)3 Crystal Group: Cubic Refractive Index: 1.72-1.748 Hardness: 7.25 Density: 3.65 Occurrence: Canada, East Africa, Pakistan, New Zealand, Ceylon, South Africa, U.S.A.
| Natural Idocrase Primarily a green color that will resemble jade.idocrase is one stone that is sometimes mistaken for jade by jewelers and consumers alike. Idocrase is from the greek and means mixed form, an allusion to its crystals showing a mixture of other mineral forms. Color: normally green, but also can be brown, yellow, blue and/or purple. Categories: semi-precious stone Chemical Composition: nesosilicate or sorosilicate Crystal Group: Tetragonal Refractive Index: 1.71 - 1.73 Hardness: 6.5 Density: 3.3 - 3.5 Occurrence: Quebec, Canada; California and the New England region of USA; Mt Vesuvius, Italy; Ural Mountains, Russia, Switzerland, East Africa
| Natural Kornerupine Kornerupine is a rare mineral occasionally used as a gemstone. It appears frequently in parcels from Ceylon and may be confused with beryl, peridot, topaz, or quartz. Color: Brown, brownish red, yellow-green, light green, blue green Categories: semi-precious stone Crystal Group: Orthorhombic Refractive Index: 1.665 ¨C 1.683 Hardness: 6.5 Density: 3.25 - 3.35 Occurrence: Ceylon, Tanzania
| Natural Musgravite Musgravite is an extremely rare member of the taaffeite family that was discovered in 1967 in the Musgrave Range of South Australia. It is also one of rare gemstones that have been sought these years for the collection at GAAJ laboratory. Color: pale olive green, grey, mauve, grey purple Categories: semi-precious stone Chemical Composition: (Fe2+,Zn,Mg)2Al6BeO12 Crystal Group: Hexagonal Refractive Index: 1.717 - 1.739 Density: 3.68 Occurrence: The Musgrave Mountain Ranges in Central Australia
| 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 Peridot Peridot is the best known gem variety of olivine, a species name for a series of magnesium-iron rich silicate minerals.It is one of the prettiest of all green gems.Most peridot formed deep inside the earth and was brought to the surface by volcanoes. Some has also come to Earth in meteorites, but this extraterrestrial peridot is extremely rare, and you're not likely to see it in a retail jewelry store. Color: Green, olive. Categories: semi-precious stone Chemical Composition: (Mg,Fe)2(SiO)4 Crystal Group: Orthorhombic Refractive Index: 1.654-1.689 Hardness: 6.5 Density: 3.34 Occurrence: China, Burma, East Africa, U.S.A., and Vietnam
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