mineral
Smoky Quartz
Silicon Dioxide (SiO2)
Hardness: 7 (Mohs scale), Color: Smoky brown to black/gray, Luster: Vitreous (glassy), Crystal structure: Hexagonal (trigonal), Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
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Physical properties
Hardness: 7 (Mohs scale), Color: Smoky brown to black/gray, Luster: Vitreous (glassy), Crystal structure: Hexagonal (trigonal), Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
Formation & geological history
Forms in igneous rocks like granite pegmatites and metamorphic rocks. The dark color is caused by natural irradiation from surrounding minerals reacting with trace aluminum impurities in the crystal lattice.
Uses & applications
Commonly used in jewelry (facets/cabochons), ornamental carvings, crystal healing collections, and historically for early sunglasses in 12th century China.
Geological facts
Cairngorm is a famous variety of smoky quartz found in the Cairngorm Mountains of Scotland. Morion is the name given to very dark, opaque specimens.
Field identification & locations
Identify by the dark translucency, lack of cleavage, and vertical striations on crystal faces. Found globally, with notable deposits in Brazil, Madagascar, and the Swiss Alps.
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Mineral/Rock
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Green Apatite on Albite
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