| Gemstone Chart |
 Natural Chalcedony
Chalcedony is a catch all term that includes many well known varieties of cryptocrystalline quartz gemstones. They are found in all 50 States, in many colors and color combinations, and in sedimentary, igneous, and metamorphic rocks.
Color: grayish, purple, white, green, blue, lavender, yellow, brown
Categories: semi-precious stone
Chemical Composition: SiO2
Crystal Group: Hexagonal
Refractive Index: 1.530 - 1.539
Hardness: 6.5
Density: 2.57 ¨C 2.64
Occurrence: Brazil, U.S.A. Germany, India, Uruguay, Austarlia, Egypt, Italy, Scotland, South Africa, Namibia, Madagascar, Mexico, Tanzania, and many other localities throughout the world.
|  Natural Diamond
Diamond is the ultimate gemstone, having few weaknesses and many strengths. It is well known that Diamond is the hardest substance found in nature.
Color: White, yellow, brown, black. Rarely, blue, red, or pink.
Categories: precious stone
Chemical Composition: C
Crystal Group: Cubic
Refractive Index: 2.417
Hardness: 10
Density: 3.52
Occurrence: Africa, Russia, Canada, Australia, India
|  Natural Prehnite
Prehnite is a hydrated calcium aluminum silicate that occurs in a soft yellow-green to apple-green color.It was a rare gemstone, most prehnite is translucent but transparent specimens are sometimes found.While you are unlikely to find it in your local jewelry store, gemstone dealers often have some supply. Deposits are found in South Africa, Australia, China, Scotland and the United States.
Color: yellow green, brown, yellow brown, oil green
Categories: semi-precious stone
Chemical Composition: (CA2Al2SI3O10(OH)2)
Crystal Group: Orthorhombic
Refractive Index: 1.61 - 1.64
Hardness: 6
Density: 2.80 - 2.95
Occurrence: China, France, U.S.A., Scotland, Australia
|  Natural Scheelite
Scheelite is a calcium tungstate mineral with the chemical formula CaWO4.With a hardness of 4.5 to 5 on the Moh's ScaleScheelite is a rather soft stone. Traditionally, it was considered a collector's gem and unsuitable for use in jewelry.
Color: Yellowish-white, brownish, orange yellow
Categories: semi-precious stone
Chemical Composition: CaWO4
Crystal Group: Tetragonal
Refractive Index: 1.918 - 1.937
Hardness: 4.5 - 5.0
Density: 5.9 - 6.1
Occurrence: Czechoslovakia; Italy; Switzerland; Finland; Cumberland, Cornwall, England; Santa Cruz, Sonora, Mexico; South Dakota, Conneticut, Colorado, Utah, California, Arizona, USA; New South Wales and Queensland, Australia; Mian Yang, and Ping Wu, Sezhuan, China; Hollinger Mine, Ontario, Canada;
|  Natural Sphene
Sphene is also known as calcium titanium silicate.It is named from the greek word for wedge, because of its typical wedge shaped crystal habit.Because of it's high dispersion and refractive index, a well cut sphene can display stunning brilliance. Sphene is somewhat soft and as a result is more suitable as a pendant than as a ring stone. Sphene is rarely very clean.
Color: Green, yellow. brown
Categories: semi-precious stone
Chemical Composition: CaTiSiO5
Crystal Group: Monoclinic
Refractive Index: (1.885-1.990,)-(1.915-2.050)
Hardness: 5.5
Density: 3.52-3.54
Occurrence: Austria, Dheirene-Madagascar, India, USA, Brazil.
|  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.
|  Natural Zircon
Zircon is a mineral belonging to the group of nesosilicates. It is one of the heaviest gemstones, which means that it will look smaller than other varieties of the same weight. Zircon occurs in a wide range of colours,the most popular colour is blue zircon. The wide variety of colours of zircon, its rarity, and its relatively low cost make it a popular collector's stone.
Color: Brown, blue, red, orange, white, green
Categories: semi-precious stone
Chemical Composition: ZrSiO4
Crystal Group: Tetragonal
Refractive Index: 1.780-1.984
Hardness: 7.5
Density: 4.00-4.73
Occurrence: Ceylon, Burma,France, Norway, East Africa,Australia, SE Asia.
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