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Quartz, Tibet.jpg
Quartz crystal cluster frae Tibet
Category Silicate mineral
(repeating unit)
Strunz classification 04.DA.05
Dana classification
Crystal symmetry Trigonal 32
Unit cell a = 4.9133 Å, c = 5.4053 Å; Z=3
Color Colourless through various colours tae black
Crystal habit 6-sidit prism endin in 6-sided pyramid (typical), drusy, fine-grained tae microcrystalline, massive
Crystal seestem α-quartz: trigonal trapezohedral class 3 2; β-quartz: hexagonal 622[1]
Twinnin Common Dauphine law, Brazil law an Japan law
Cleavage {0110} Indistinct
Fractur Conchoidal
Tenacity Brickle
Mohs scale hairdness 7 – lawer in impure varieties (definin mineral)
Luster Vitreous – waxy tae dull when massive
Streak White
Diaphaneity Transparent tae near opaque
Specific gravity 2.65; variable 2.59–2.63 in impure varieties
Optical properties Uniaxial (+)
Refractive index nω = 1.543–1.545
nε = 1.552–1.554
Birefringence +0.009 (B-G interval)
Pleochroism None
Meltin pynt 1670 °C (β tridymite) 1713 °C (β cristobalite)[1]
Solubility Insoluble at STP; 1 ppmmass at 400 °C an 500 lb/in2 tae 2600 ppmmass at 500 °C an 1500 lb/in2[1]
Ither characteristics Piezoelectric, mey be triboluminescent, chiral (hence optically active if nae racemic)
References [2][3][4][5]

Quartz is the seicont maist abundant mineral in the Yird's continental crust, efter feldspar. It is made up o a continuous framework o SiO4 siliconoxygen tetrahedra, wi lika oxygen bein shared atween twa tetrahedra, giein an oweraw formula SiO2.

Thare mony different varieties o quartz, several o whilk is semi-precious gemstanes. Inspecially in Europe an the Middle East, varieties o quartz haes been syne antiquity the maist commonly uised minerals in the makkin o jewelry an hairdstane carvins.

The wird "quartz" is derived frae the German wird "Quarz" and its Middle Heich German auncestor "twarc", that belike oreeginatit in Slavic (cf. Czech tvrdý ("haird"), Polish twardy ("haird")).[6]

References[eedit | eedit soorce]

  1. 1.0 1.1 1.2 Deer, W. A., R. A. Howie and J. Zussman, An Introduction to the Rock Forming Minerals, Logman, 1966, pp. 340–355 ISBN 0-582-44210-9
  2. Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W. and Nichols, Monte C. (ed.). "Quartz". Handbook of Mineralogy (PDF). III (Halides, Hydroxides, Oxides). Chantilly, VA, US: Mineralogical Society of America. ISBN 0962209724. 
  3. Quartz. Mindat.org. Retrieved on 2013-03-07.
  4. Quartz. Webmineral.com. Retrieved on 2013-03-07.
  5. Hurlbut, Cornelius S.; Klein, Cornelis (1985). Manual of Mineralogy (20 ed.). ISBN 0-471-80580-7. 
  6. Harper, Douglas. "quartz". Online Etymology Dictionary.