mineral

Smoky Quartz (Tumbled)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Translucent brownish-grey to smoky yellow; Luster: Vitreous (glassy); Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Translucent brownish-grey to smoky yellow
Luster: Vitreous (glassy)

Identified March 30, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the igneous process in granite pegmatites or hydrothermal veins. The smoky color is caused by natural irradiation of aluminum-containing rock crystal during its geological history, often spanning millions of years.

Uses & applications

Commonly used in jewelry as a gemstone, as well as in the production of quartz watches, piezoelectric devices, and by collectors for its aesthetic and 'grounding' metaphysical properties.

Geological facts

Smoky Quartz is the national gem of Scotland, where it is known as 'Cairngorm.' It was used in Ancient China to make the first-ever sunglasses to conceal the facial expressions of judges in courts.

Field identification & locations

Identify by its characteristic 'smoky' translucency and hardness (it will scratch glass). Commonly found in the Swiss Alps, Brazil, Madagascar, and the United States (Colorado). Field identification relies on the lack of cleavage and its smoke-like inclusions.