Topaz facts for kids

Kids Encyclopedia Facts
Topaz
TopazUSGOV.jpg
A group of topaz crystals on matrix
General
Category Silicate mineral
Formula
(repeating unit)
Al2SiO4(F,OH)2
Strunz classification 9.AF.35
Crystal symmetry Orthorhombic dipyramidal
H-M symbol: (2/m 2/m 2/m)
Space group: Pbnm
Unit cell a = 4.65 Å, b = 8.8 Å,
c = 8.4 Å; Z = 4
Identification
Color Colorless (if no impurities), blue, brown, orange, gray, yellow, green, pink and reddish pink
Mohs scale hardness 8 (defining mineral)
Luster Vitreous
Birefringence δ = 0.010

Topaz is a rock. It includes the minerals aluminium and fluorine with the chemical formula Al2SiO4(F,OH)2.

Color and varieties

Pure topaz is colorless and transparent but they usually have colors. The typical topaz is wine, yellow, pale gray, reddish-orange, or blue brown. It can also be made white, pale green, blue, gold, or pink (rare).

Orange topaz, also known as precious topaz, is the traditional November birthstone, the symbol of friendship, and the state gemstone for the US state of Utah.

Imperial topaz is yellow, pink (rare, if natural) or pink-orange. Some imperial topaz stones can fade if they are exposed too much in the sunlight.

Blue topaz is the US state Texas' gemstone.

Mystic topaz is colorless topaz which has been artificially coated, making it rainbow-colored.

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Topaz Facts for Kids. Kiddle Encyclopedia.