mineral
Smoky Quartz
Silicon Dioxide (SiO2)
Hardness: 7 on Mohs scale; Color: Brownish grey to black; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (Trigonal); Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Brownish grey to black
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on Mohs scale; Color: Brownish grey to black; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (Trigonal); Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65
Formation & geological history
Forms in igneous rocks (pegmatites) and metamorphic rocks. The dark color results from natural irradiation of trace aluminum impurities within the quartz crystal lattice.
Uses & applications
Used in gemstone manufacturing, jewelry, metaphysical collecting, and historically in the construction of early sunglasses in China.
Geological facts
The name 'smoky' is derived from its appearance, which looks like it is filled with smoke. Very dark, opaque varieties are specifically called 'morion'.
Field identification & locations
Identify by its smoky translucence, hexagonal habit, and lack of cleavage. Common in Brazil, Madagascar, and the Swiss Alps.
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Other mineral specimens
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Sandstone with Mineral Veining or Crust
Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)
sedimentary
Schist
Schist
Metamorphic
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Nephrite Jade
Nephrite
Mineral/Rock