mineral

Smoky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Grayish-brown to black; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

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

Identified May 12, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Grayish-brown to 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 through the crystallization of silica-rich fluids. The smoke-like color is caused by natural irradiation acting on traces of aluminum within the quartz structure.

Uses & applications

Commonly used in jewelry, decorative carvings, and as healing crystals in the metaphysical community. Used in watchmaking and optics due to piezoelectric properties.

Geological facts

The dark color can be deepened through artificial irradiation or turned yellow into citrine through heat treatment. Cairngorm is a famous variety found in the Scottish Highlands.

Field identification & locations

Identify by its transparency, smoky color, and lack of cleavage (it breaks in curved surfaces). Commonly found in Brazil, USA (Colorado), and Madagascar.