mineral
Smoky Quartz
Silicon Dioxide (SiO2)
Hardness of 7 on the Mohs scale. Color ranges from light grayish-brown to deep black. Luster is vitreous (glassy). Crystal structure is trigonal, typically forming hexagonal prisms. Conchoidal fracture with no true cleavage. Specific gravity is 2.65.
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Physical properties
Hardness of 7 on the Mohs scale. Color ranges from light grayish-brown to deep black. Luster is vitreous (glassy). Crystal structure is trigonal, typically forming hexagonal prisms. Conchoidal fracture with no true cleavage. Specific gravity is 2.65.
Formation & geological history
Formed in igneous, metamorphic, and pegmatitic environments. The smoky color is naturally produced when free silicon, formed from the silicon dioxide by natural irradiation, is activated.
Uses & applications
Used in jewelry, decorative carvings, metaphysical practices, and optical components.
Geological facts
Smoky quartz is the national gemstone of Scotland, where it has a long history and is known as cairngorm. Dark, opaque varieties are sometimes called morion.
Field identification & locations
Easily identified by its characteristic brown-to-black color and vitreous luster in quartz crystals. Found worldwide, with notable deposits in Brazil, Switzerland, Madagascar, and the United States.
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