Gemstone Chart |
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 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.
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