mineral
Smoky Quartz
Silicon Dioxide (SiO₂)
AI-generated identification · may be incorrectHardness: 7 (Mohs scale), Color: Brownish-grey to black, Luster: Vitreous (glassy), Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
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Physical properties
Hardness: 7 (Mohs scale), Color: Brownish-grey to black, Luster: Vitreous (glassy), Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
Formation & geological history
Formed in igneous and metamorphic rocks, particularly pegmatites and hydrothermal veins. The smoky color is caused by natural irradiation of trace aluminum impurities within the quartz.
Uses & applications
Popular in jewelry (faceted or cabochon), ornamental carvings, and widely collected as mineral specimens. In industry, quartz is used for its piezoelectric properties and in glass making.
Geological facts
Smoky quartz is the national gem of Scotland, where it is often called Cairngorm. Its color can range from a light 'tea' brown to a nearly opaque 'Morion' black.
Field identification & locations
Identify by its glassy luster, lack of cleavage, and the presence of internal fractures or inclusions. Commonly found in Brazil, USA (Colorado), Switzerland, and Madagascar.
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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