Topaz
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| Topaz | |
|---|---|
 | |
| General | |
| Category | Nesosilicate meenerals |
| Formula (repeatin unit) | Al2SiO4(F,OH)2 |
| Strunz clessification | 9.AF.35 |
| Creestal seestem | Orthorhombic |
| Creestal cless |
Dipyramidal (mmm) 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 | |
| Colour | Colourless (if na impurities), blue, broun, orange, gray, yellae, green, pink an reiddish pink |
| Creestal habit | Prismatic creestals wi faces striatit parallel tae lang dimension; an aa columnar, compact, massive |
| Cleavage | [001] Perfect |
| Fractur | Subconchoidal tae uneven |
| Mohs scale haurdness | 8 (definin meeneral) |
| Skinkle | Vitreous |
| Streak | White |
| Diaphaneity | Transparent |
| Speceefic gravity | 3.49–3.57 |
| Optical properties | Biaxial (+) |
| Refractive index |
nα = 1.606–1.629 nβ = 1.609–1.631 nγ = 1.616–1.638 |
| Birefringence | δ = 0.010 |
| Pleochroism | Waik in thick sections X = yellae; Y = yellae, violet, reiddish; Z = violet, bluish, yellae, pink |
| Ultraviolet fluorescence | Short UV=gowden yellae; Lang UV=cream |
| References | [1][2][3][4] |
Topaz is a silicate meeneral o aluminium an fluorine wi the chemical formula Al2SiO4(F,OH)2. Topaz creestallises in the orthorhombic seestem, an its creestals are maistly prismatic terminatit bi pyramidal an ither faces.
References[eedit | eedit soorce]
- ↑ Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy, 20th ed., ISBN 0-471-80580-7
- ↑ Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C., eds. (1995). "Topaz". Handbook of Mineralogy (PDF). II (Silica, Silicates). Chantilly, VA, US: Mineralogical Society of America. ISBN 978-0-9622097-1-0. Retrieved December 5, 2011.
- ↑ Topaz. Mindat.org. Retrieved on 2011-10-29.
- ↑ Topaz. Webmineral.com. Retrieved on 2011-10-29.
