| Gemstone Chart |
 Natural Citrine
Citrine is any quartz crystal or cluster that is yellow or orange in color. Although often cut as a gemstone, citrine is actually somewhat rare in nature.
Color: Yellow, orange
Categories: semi-precious stone
Chemical Composition: SiO2
Crystal Group: Trigonal
Refractive Index: 1.544-1.553
Hardness: 7
Occurrence: Brazil, Uruguay, Mexico, Russia, USA.
|  Natural Hessonite
Hessonite is one of the gem varieties of the garnet mineral, grossular. Hessonite is usually cinnamon brown and has been called "cinnamon stone". Hessonite can also be orange; this color is becoming common on the gem markets.
Color: Brownish-orange, brownish yellow, aurora red
Categories: semi-precious stone
Chemical Composition: Ca3Al2(SIO4)3
Crystal Group: Cubic
Refractive Index: 1.72-1.74
Hardness: 7.25
Density: 3.65
Occurrence: Sri Lanka, Mexico, Brazil, Canada, Madagascar
|  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 Scapolite
Scapolite is actually the name of a series between the sodium chloride rich mineral called marialite and the calcium carbonate rich mineral meionite.Scapolite was originally discovered in 1913 in the Mogok Stone Tract in upper Burma (Myanmar). Scapolite is a rare and little known gemstone. It is a beautiful gem that comes in many colors.
Color: white, yellow, violet,pink
Categories: semi-precious stone
Chemical Composition: Na4Al3Si9O24Cl /CA4Al6Si6O24CO3
Crystal Group: Tetragonal
Refractive Index: 1.54 - 1.577
Hardness: 6
Density: 2.6-2.71
Occurrence: Kenya, Mozambique, Madagascar, Burma, Brazil, 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 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.
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