Gemstone Chart |
Natural Tourmaline Tourmaline is actually a group of several different minerals which have similar crystal structures, but complex and variable chemical formulas. Tourmaline is the most varicolored of all gemstones. It occurs in all colors, but red, green, and multicolored are its most famous gem colors. Color: blue, bluish green, green, greenish blue, green-blue or blue-green, greenish yellow, orangy red, red, red-orange or orange-red, red-purple or purple-red, slightly purplish red, slightly yellowish green, strongly purplish red, strongly yellowish green, very slightly bluish green, yellowish green, yellow-green or green-yellow, colorless, brown, pink 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, East Africa, Nigeria, Madagascar, U.S.A.
| Natural Triplite Triplite is a rare fluoro-hydroxide phosphate mineral that forms in phosphate rich granitic pegmatites and high temperature hydrothermal veins. The name is from the Greek triplos for triple, in reference to the three cleavage directions. It is a very gemstones and few cut stones have been ever reported. Color: brightly coloured (brown, salmon, flesh-red) Categories: semi-precious stone Chemical Composition: (Mn,Fe2+)2(PO4)(F,OH) Crystal Group: Monoclinic Refractive Index: 1.650 - 1.680 Hardness: 5 - 5.5 Density: 3.44 - 3.90 Occurrence: the Shigar Valley, Pakistan; China; France, Bavaria, Germany; Kimito, Finland; Karibib, Namibia; Maine, and Connecticut, Arizona and Colorado in the United States.
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