mineral
Smoky Quartz
Silicon Dioxide (SiO2)
Mohs hardness: 7. Color: translucent brown to gray-black. Luster: vitreous. Crystal structure: hexagonal/trigonal. No cleavage; conchoidal fracture. Specific gravity: 2.65.
- Hardness
- 7
- Color
- translucent brown to gray-black
- Luster
- vitreous
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Physical properties
Mohs hardness: 7. Color: translucent brown to gray-black. Luster: vitreous. Crystal structure: hexagonal/trigonal. No cleavage; conchoidal fracture. Specific gravity: 2.65.
Formation & geological history
Forms in igneous and metamorphic rocks, particularly granites and pegmatites. The smoky color is produced by natural gamma irradiation of trace aluminum impurities within the crystal lattice over millions of years.
Uses & applications
Widely used for ornamental jewelry, metaphysical collecting, and as a source of silicon for electronics in lower-grade forms.
Geological facts
The smoky color can be deeped or altered by artificial irradiation or heat treatment. It was famously used to make the first 'sunglasses' in 12th century China to block the glare from the sun.
Field identification & locations
Identify in the field by its distinct smoky transparency, hardness (scratches glass), andLack of cleavage. Commonly found in Brazil, Madagascar, and the Swiss Alps.
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Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
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
Granite
Granite (Phaneritic intrusive igneous rock)
igneous