mineral

Smoky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Pale yellowish-brown to grayish-brown; Luster: Vitreous (glassy); Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Pale yellowish-brown to grayish-brown
Luster: Vitreous (glassy)

Identified July 18, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous or metamorphic environments, primarily within hydrothermal veins or pegmatites. The smoky color results from natural irradiation of aluminum-bearing quartz over millions of years.

Uses & applications

Used widely in lapidary work for jewelry, as ornamental interior design pieces, and as a popular specimen for mineral collectors. In industry, high-purity quartz is used in electronics and glass-making.

Geological facts

Smoky quartz is the national gem of Scotland, where it is known as 'Cairngorm'. The dark color can often be removed or lightened by heating the specimen.

Field identification & locations

Identify by its characteristic glassy luster and ability to scratch glass. It often shows internal fractures or phantoms. Commonly found in mountainous regions globally, such as the Alps, Brazil, and the USA.