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Also read about: Gem Meanings -or- Gem Lore GEM PROPERTIES Renowned and valued for their beauty, gemstones are natural forms of matter that can be cut and polished for use as jewelry or other ornamental purposes. Precious and Semi-Precious Five particular stones - diamond, ruby, sapphire, emerald, and amethyst were once referred to as precious stones primarily because of historical and ceremonial use while other stones were referred to as semiprecious stones. Durability is a twofold test of a mineral's hardness and toughness. One misconception is that these are the same thing. However, hardness refers to a mineral's resistance to scratching while toughness refers to its resistance to breaking. A diamond, for example, is the hardest of all minerals; but, it can be crushed with enough force. Jade, on the other hand, is quite susceptible to scratching; but, it is considered one of the toughest gemstones. The hardness of a gemstone is determined by the Mohs scale, which ranges from 1 to 10. Talc, which is 1 on the scale, is softest, while diamonds are the hardest at 10. Mineral gemstones are naturally formed rocks found in the earth's surface. There are 16 groups of mineral gemstones, including: Beryl, Chrysoberyl, Corundum, Diamond, Feldspar, Garnet, Jade, Lapis Lazuli, Opal, Peridot, Quartz, Spinel, Topaz, Tourmaline, Turquoise, and Zircon. Organic gemstones are the result of natural transformations which are not as durable as mineral gemstones, and consist of four groups: Amber - a fossil resin found in the sap of ancient tree pines, usually lacks a crystalline structure. It is most often brown or semitransparent and mined. Coral - crafted when a small marine animal known as a coral polyp extracts calcium carbonate from the sea to build a protective home for itself. The result of gem coral ranges from semitranslucent to opaque and can be white, pink, orange, red, blue, violet, gold, or black. Jet - a black coal that can be used as beads or for bracelets. Pearl - formed inside an oyster, or any other mollusk that deposits substances inside of its housing. Mollusks creating pearls can be found in either fresh or salt water, but salt water pearls are often more sought after for use in earrings, bracelets, and necklaces. Most pearls are white, but they also come in a variety of other colors, including black. Other classifications of gemstones include crystal structure, optical characteristics, and specific gravity. Read about the Power and Meaning of Gemstones |