mineral

Smoky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Translucent grey to brownish-black; Luster: Vitreous; Crystal structure: Trigonal/Hexagonal prism; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Translucent grey to brownish-black
Luster: Vitreous

Identified July 9, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Translucent grey to brownish-black; Luster: Vitreous; Crystal structure: Trigonal/Hexagonal prism; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Formation & geological history

Formed in igneous or metamorphic rocks like granite and gneiss. The smoky color is produced when natural radiation from surrounding rocks causes impurities of aluminum in the quartz crystal to change oxidation states.

Uses & applications

Used in jewelry, decorative ornaments, and crystal healing collections. High-quality piezoelectric quartz is used in electronics, though synthetic quartz is now more common.

Geological facts

The dark color can sometimes be so intense that the crystal appears opaque black, often referred to as 'Morion'. It was used in China as early as the 12th century to make the lenses for the first sunglasses.

Field identification & locations

Identified by its hexagonal crystal shape with horizontal striations on the prism faces. Frequently found in pegmatite veins. Major sources include Brazil, Madagascar, and the Swiss Alps.