mineral

Smoky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 on the Mohs scale. Color: Translucent to opaque smokey brown, grey, or black. Luster: Vitreous (glassy). Crystal Structure: Hexagonal (trigonal system). Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Hardness: 7 on the Mohs scale
Color: Translucent to opaque smokey brown, grey, or black
Luster: Vitreous (glassy)

Identified March 15, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous or metamorphic rocks, particularly pegmatites and hydrothermal veins. The color is caused by natural irradiation of aluminum impurities within the crystal lattice over millions of years.

Uses & applications

Used in gemstone jewelry (faceting and cabochons), ornamental carvings, and by collectors. Historically used in early sunglasses in China and for various metaphysical purposes.

Geological facts

The dark color can often be removed by heating. In Cairngorm, Scotland, it is known as 'Cairngorm' and is the national gemstone of Scotland. Naturally black, nearly opaque varieties are referred to as 'Morion'.

Field identification & locations

Identify in the field by its transparency, smoky tint, and lack of cleavage planes. Found globally with major deposits in Brazil, Switzerland (the Alps), USA (Pikes Peak), and Madagascar. Collectors look for terminated crystal points.