Quartz

Quartz
Quartz crystal cluster from Tibet
General
CategoryOxide mineral
Chemical formulaSilica (silicon dioxide, SiO2)
Strunz classification04.DA.05
Dana classification75.01.03.01
Identification
ColorColorless through various colors to black
Crystal habit6-sided prism ending in 6-sided pyramid (typical), drusy, fine-grained to microcrystalline, massive
Crystal systemα-quartz: trigonal trapezohedral class 3 2; β-quartz: hexagonal 622[1]
TwinningCommon Dauphine law, Brazil law and Japan law
Cleavage{0110} Indistinct
FractureConchoidal
TenacityBrittle
Mohs scale hardness7 - lower in impure varieties
LusterVitreous - waxy to dull when massive
StreakWhite
DiaphaneityTransparent to nearly opaque
Specific 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
Melting point1670 °C (β tridymite) 1713 °C (β cristobalite)[1]
Solubility1 ppmmass at 400 °C and 500 lb/in2 to 2600 ppmmass at 500 °C and 1500 lb/in2[1]
Other characteristicsPiezoelectric, pyroelectric, may be triboluminescent
References[2][3][4][5]


ItokasiÀtúnṣe

  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. Handbook of Mineralogy. Quartz
  3. Mindat. Quartz
  4. Webmineral. Quartz
  5. Hurlbut, Cornelius S.; Klein, Cornelis (1985). Manual of Mineralogy (20 ed.). ISBN 0-471-80580-7.