Quartz

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Quartz
Quartz, Tibet.jpg
Quartz creestal cluster frae Tibet
General
Category Silicate mineral
Formula
(repeatin unit)
SiO2
Strunz clessification 04.DA.05
Dana clessification 75.01.03.01
Creestal seestem α-quartz: trigonal trapezohedral class 3 2; β-quartz: hexagonal 622[1]
Space group Trigonal 32
Unit cell a = 4.9133 Å, c = 5.4053 Å; Z=3
Identification
Colour Colourless through various colours tae black
Creestal habit 6-sidit prism endin in 6-sided pyramid (typical), drusy, fine-grained tae microcrystalline, massive
Twinnin Common Dauphine law, Brazil law an Japan law
Cleavage {0110} Indistinct
Fractur Conchoidal
Tenacity Brickle
Mohs scale haurdness 7 – lawer in impure varieties (definin mineral)
Skinkle Vitreous – waxy tae dull when massive
Streak White
Diaphaneity Transparent tae near opaque
Speceefic 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 chairacteristics Piezoelectric, mey be triboluminescent, chiral (hence optically active if nae racemic)
References [2][3][4][5]

Quartz is the seicont maist abundant meeneral 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 gemstones. Ispecially in Europe an the Middle East, varieties o quartz haes been syne antiquity the maist commonly uised meenerals in the makkin o jewelry an hairdstane carvins.

The wird "quartz" is derived frae the German wird "Quarz" an its Middle Heich German auncestor "twarc", that belike oreeginatit in Slavic (cf. Czech tvrdý ("haird"), Pols 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.