Clinfowiki
| Topaz | |
|---|---|
 Topaz crystal on matrix | |
| General | |
| Category | Nesosilicate |
| 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 |
| References | [1][2][3][4] |
Topaz is a silicate mineral. Along with silicate, it includes the chemical elements 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 made by small impurities. 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.[5]
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.[6][7]
Blue topaz is the US state Texas' gemstone.[8]
Mystic topaz is colorless topaz which has been artificially coated, making it rainbow-colored.[9]
Gallery
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Colorless topaz, Minas Gerais, Brazil -
A cut blue topaz -
A red topaz -
Imperial Topaz Gem -
Facet Cut Topaz Gemstones in various colors, including mystic.
Related pages
References
- ↑ Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy, 20th ed., ISBN 0-471-80580-7
- ↑ Topaz. Handbook of Mineralogy. (PDF) . Retrieved on 2011-10-29.
- ↑ Topaz. Mindat.org. Retrieved on 2011-10-29.
- ↑ Topaz. Webmineral.com. Retrieved on 2011-10-29.
- ↑ Utah State Gem – Topaz Archived 2012-11-14 at the Wayback Machine. Pioneer.utah.gov (2010-06-16). Retrieved on 2011-10-29.
- ↑ Imperial Topaz Archived 2009-05-13 at the Wayback Machine, Natural History Museum of Los Angeles County
- ↑ Gemstones & Gemology – Topaz Archived 2011-08-08 at the Wayback Machine, Emporia State University
- ↑ State Gem – Texas Blue Topaz. State Gemstone Cut – Lone Star Cut. state.tx.us
- ↑ Mystic Topaz, Consumer Information. Farlang.com (2008-10-30). Retrieved on 2011-10-29.
Other websites
- Pink Topaz, Biblical Topaz References Archived 2009-08-15 at the Wayback Machine Farlang – gem information and full text historical references
- Topaz and other minerals found at Topaz Mountain, Juab County Archived 2013-08-27 at the Wayback Machine, Utah Geological Survey
| Authority control: National |
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