User:Maximum1998
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Quartz (from German Quarzⓘ[1]) is the most abundant mineral in the Earth's continental crust (although feldspar is more common in the world as a whole). It is made up of a lattice of silica (SiO2) tetrahedra. Quartz has a hardness of 7 on the Mohs scale and a density of 2.65 g/cm³.
Quick Facts Quartz, General ...
Quartz | |
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![]() Quartz crystal group from Arkansas | |
General | |
Category | Mineral |
Formula (repeating unit) | Silica (silicon dioxide, SiO2) |
Crystal system | rhombohedral class 32 |
Identification | |
Color | Clear (if no impurities); also see Varieties |
Crystal habit | 6-sided prism ending in 6-sided pyramid (typical) |
Twinning | Dauphine law, Brazil law and Japan law |
Cleavage | None |
Fracture | Conchoidal |
Mohs scale hardness | 7 - lower in impure varieties |
Luster | Vitreous/glossy |
Streak | White |
Diaphaneity | Transparent to translucent |
Specific gravity | 2.65 constant; variable 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 |
Melting point | 1650 (±75) °C |
Solubility | 11.0 +/- 1.1 PPM @ 25 C |
Other characteristics | Piezoelectric |
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