Quartz

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Quartz
Quartz, Tibet.jpg
Quartz creestal cluster frae Tibet
General
CategorySilicate mineral
Formula
(repeatin unit)
SiO2
Strunz clessification04.DA.05
Dana clessification75.01.03.01
Creestal seestemα-quartz: trigonal trapezohedral class 3 2; β-quartz: hexagonal 622[1]
Space groupTrigonal 32
Unit cella = 4.9133 Å, c = 5.4053 Å; Z=3
Identification
ColourColourless through various colours tae black
Creestal habit6-sidit prism endin in 6-sided pyramid (typical), drusy, fine-grained tae microcrystalline, massive
TwinninCommon Dauphine law, Brazil law an Japan law
Cleavage{0110} Indistinct
FracturConchoidal
TenacityBrickle
Mohs scale haurdness7 – lawer in impure varieties (definin mineral)
SkinkleVitreous – waxy tae dull when massive
StreakWhite
DiaphaneityTransparent tae near opaque
Speceefic gravity2.65; variable 2.59–2.63 in impure varieties
Optical propertiesUniaxial (+)
Refractive indexnω = 1.543–1.545
nε = 1.552–1.554
Birefringence+0.009 (B-G interval)
PleochroismNone
Meltin pynt1670 °C (β tridymite) 1713 °C (β cristobalite)[1]
SolubilityInsoluble at STP; 1 ppmmass at 400 °C an 500 lb/in2 tae 2600 ppmmass at 500 °C an 1500 lb/in2[1]
Ither chairacteristicsPiezoelectric, 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 conteenous 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.CS1 maint: multiple names: eeditors leet (link)
  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.CS1 maint: multiple names: authors leet (link)
  6. Harper, Douglas. "quartz". Online Etymology Dictionary.