mineral

Smoky Quartz

SiO2 (Silicon Dioxide)

Hardness: 7 (Mohs scale); Color: Brown, gray, or black; Luster: Vitreous (glassy); Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Brown, gray, or black
Luster: Vitreous (glassy)

Identified April 13, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Brown, gray, or black; Luster: Vitreous (glassy); Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed in igneous or metamorphic rocks (common in pegmatites) and hydrothermal veins. The color is caused by natural irradiation of aluminum-bearing quartz over millions of years.

Uses & applications

Used widely in jewelry (gemstone), metaphysical collecting, and historically in early sunglasses (ancient China).

Geological facts

Smoky quartz is the national gem of Scotland, where it is known as 'Cairngorm.' Some of the darkest varieties are called 'Morion.' It is often found alongside feldspar and mica.

Field identification & locations

Identify in the field by its glassy luster, lack of cleavage, and characteristic translucent to transparent brown/smoke color. It is more resistant to weathering than surrounding minerals and can be found in stream beds or within granite cavities.