mineral

Smoky Quartz

Silicon Dioxide (SiO2) with aluminum impurities

Hardness: 7 on Mohs scale; Color: translucent brownish-gray to black; Luster: Vitreous (glass-like); Crystal structure: Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: translucent brownish-gray to black
Luster: Vitreous (glass-like)

Identified March 23, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: translucent brownish-gray to black; Luster: Vitreous (glass-like); Crystal structure: Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Formation & geological history

Formed in igneous and metamorphic rocks like granite or pegmatite. The smoky color is caused by natural gamma radiation from the surrounding rock acting on trace amounts of aluminum within the quartz lattice over millions of years.

Uses & applications

Used primarily in lapidary work for jewelry, decor, and as metaphysical 'healing crystals'. Historically used for making the first sunglasses in 12th century China.

Geological facts

Smoky quartz can also be created artificially by irradiating clear rock crystal. The darkest, almost opaque variety is known as 'Morion'. It is the national gem of Scotland, where it is often referred to as 'Cairngorm'.

Field identification & locations

Identify by its glass-like appearance, lack of cleavage, and common conchoidal (shell-like) fractures. It is frequently found in high-altitude mountain ranges or granite-heavy regions like the Swiss Alps, Brazil, or the US Rockies.

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