Gemstone Chart |
Natural Sapphirine Sapphirine is a rare mineral, a silicate of magnesium and aluminium.Though Sapphirine clearly falls into the "rare stone" category, it is a relatively durable stone with a Moh's hardness of 7.5. Sapphirine's very distinctive appearance along with their somewhat unusual durability have made them fairly popular with collectors. Color: Pale blue, bluish gray, greenish gray, green, purplish pink Categories: semi-precious stone Crystal Group: Monoclinic Refractive Index: 1.714-1.723 Hardness: 7.5 Density: 3.4-3.5 Occurrence: U.S.A., U.K., Sweden, Czechoslovakia, Japan, South Africa, Greenland, Madagascar, Italy, Sri Lanka
| Natural Sillimanite Sillimanite is an alumino-silicate mineral with the chemical formula Al2SiO5. Sillimanite is a very rare trimorph and it has a common variety called fibrolite. Color: violet blue, grey green, colorless, brown, green, Categories: semi-precious stone Chemical Composition: Al2OSiO4 Crystal Group: Orthorhombic Refractive Index: 1.658 - 1.678 Hardness: 6 - 7.5 Density: 3.25 Occurrence: France, Madagascar, U.S.A., Sri Lanka, Burma. Kenya
| Natural Spessartite The Spessartite is one of the most popular of all garnets. It is highly desired by collectors, jewelry designers and gem lovers.The sources for gem quality spessartine are Sri Lanka and Brazil. Color: Orange, yellow, brown Categories: semi-precious stone Chemical Composition: Mn3Al2(SiO4)3 Crystal Group: Cubic Refractive Index: 1.79-1.81 Hardness: 7.25 Density: 4.14-4.20 Occurrence: Germany, Ceylon, Burma, Nigeria, Maevatanana-Madagascar, Isoanala-Madagascar, East Africa.
| Natural Spinel Spinel is the magnesium aluminium member of the larger spinel group of minerals. It has the formula MgAl2O4.Pure spinel is white, but impurities give it a wide range of colors.Almost all colors are used in jewelry, but the most valuable and popular color is the deep red. Spinel is cut into gems for use as jewelry. The deep-red variety, known as ruby spinel, is the most prized form. Color: orange, pink, black, blue, lavender, mauve, greenish blue, and vivid red Categories: semi-precious stone Chemical Composition: MgAl2O4 Crystal Group: Cubic Refractive Index: 1.718 (-.006,+.044) Hardness: 8 Density: 3.60 (-.03, +.30) Occurrence: Mogok, Burma; Sri Lanka; Amboseli district, Kenya; Jemaa district, Nigeria; Matombo, Umba, and Tunduru Tanzania; Hunza, Pakistan; Pamir range, Tajikstan; Luc Yen, Vietnam; Madagascar; Australia; Sweden; Brazil.
| Natural Taaffeite The chemical formula of mineral Taaffeite is indicated by BeMgAl4O8 or Beryllium Magnesium Aluminum Oxide. Taaffeite actually belongs to the Oxides and Hydroxides mineral class. Taaffeite is one of the beautiful and Rarest gems in the world. Color: Mauve, reddish violet, brownish-purple, pink, red, blue. Categories: semi-precious stone Chemical Composition: Beryllium magnesium aluminate wi Crystal Group: Hexagonal Refractive Index: 1.71-1.72. Hardness: 8 - 8.5 Density: 3.60 - 3.71 Occurrence: Tunduru, Tanzania; Sri Lanka
| Natural Topaz Topaz is a silicate mineral most often found in igneous rocks of felsic composition. It is a common gemstone that has been used for centuries in jewelry. Gem quality topaz most commonly occurs in nature as a colorless crystal. It is a very popular gemstone. Color: colorless, blue, yellow-brown, pinkish orange, red-orange, red-brown, tan. Categories: semi-precious stone Chemical Composition: AL(F,OH)2SIO4 Crystal Group: Orthorhombic Refractive Index: 1.629 - 1.637 Hardness: 8 Density: 3.52 - 3.56 Occurrence: Brazil, Sri Lanka, Nigeria, Germany, Australia, Japan, Russia, Ireland, Zimbabwe.
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