Gemstone Chart |
Natural Emerald Emerald, the green variety of the mineral beryl, is the most famous and favored green gemstone.The majority of the worlds gem quality Emeralds come from the Muzo area of Colombia. Color: Blue, Green Blue Categories: precious stone Chemical Composition: Be3Al2(SiO3)6 Crystal Group: Hexagonal Refractive Index: 1.577(+-.016), 1.583 (+-.017) Hardness: 7.5-8 Density: 2.72 (-.05, +.12) Occurrence: Brazil, Pakistan,Russia, East Africa, India, Madagascar, Columbia
| 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.
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