Mineral
Smoky Quartz
Silicon dioxide (SiO2)
AI-generated identification · may be incorrectHardness: 7 (Mohs scale), Color: light grayish-brown to dark black, Luster: vitreous (glassy), Crystal structure: trigonal, Cleavage: poor/none, Specific gravity: 2.65
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Physical properties
Hardness: 7 (Mohs scale), Color: light grayish-brown to dark black, Luster: vitreous (glassy), Crystal structure: trigonal, Cleavage: poor/none, Specific gravity: 2.65
Formation & geological history
Forms in igneous and metamorphic rocks, often pegmatites and hydrothermal veins. The smoky color is generated by natural irradiation of aluminum-bearing quartz over millions of years.
Uses & applications
Used in jewelry, decorative items, carving, and as a popular collector's mineral.
Geological facts
Smoky quartz is the national gem of Scotland. Very dark, almost opaque varieties are known as 'morion'. Unlike some gems, its color can fade if exposed to prolonged sunlight and can be altered by heat treatment.
Field identification & locations
Identify by its characteristic smoky brown/gray color, vitreous luster, conchoidal fracture, and hardness of 7 (will scratch glass). Commonly found in Brazil, Madagascar, USA (Colorado), and the Swiss Alps.
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Other mineral specimens
Gneiss or Schist
Gneiss or Mica Schist with Garnet
Metamorphic
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Tumbled granite
Granite, a coarse-grained felsic intrusive igneous rock
igneous
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Pegmatite with Tourmaline and Quartz
Igneous Pegmatite
igneous
Granite
Granite (Phaneritic intrusive igneous rock)
igneous