mineral

Smoky Quartz

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale; Color: Grayish-brown to black; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (Trigonal); Cleavage: Indistinct; Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Grayish-brown to black
Luster: Vitreous (glassy)

Identified May 14, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Grayish-brown to black; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (Trigonal); Cleavage: Indistinct; Specific Gravity: 2.65

Formation & geological history

Formed in igneous or metamorphic rocks through the crystallization of magma or hydrothermal fluids. The color is caused by natural irradiation of aluminum-bearing quartz.

Uses & applications

Used frequently in jewelry (beads, faceted stones), as ornamental stones for collection, and in some optical or electronic applications.

Geological facts

Smoky quartz is the national gem of Scotland, where it is often referred to as 'Cairngorm' after the mountains where it was historically mined.

Field identification & locations

Identified in the field by its hardness (scratches glass), conchoidal fracture, and characteristic smoky translucency. Commonly found in granite pegmatites.