mineral

Smoky Quartz

Quartz (Silicon Dioxide, SiO2)

Hardness: 7 on Mohs scale; Color: Grayish-brown to brownish-black translucent; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture.

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

Identified June 21, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Grayish-brown to brownish-black translucent; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture.

Formation & geological history

Formed in intrusive igneous rocks like granites or metamorphic rocks through the crystallization of silica-rich fluids. The dark smoky color is caused by natural irradiation of aluminum impurities within the crystal lattice.

Uses & applications

Used extensively in jewelry as a gemstone, in decorative carvings, and in alternative healing practices. Industrial quartz is used in electronics and glass manufacturing.

Geological facts

Smoky quartz was used in the first sunglasses, which originated in China in the 12th century, to protect eyes from glare. It is also the national gem of Scotland, where it is known as Cairngorm.

Field identification & locations

Identify in the field by its hardness (scratches glass), lack of cleavage, and translucent smoky appearance. Commonly found in pegmatites and alpine-type fissures.