mineral

Smoky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Brown to black, smoky gray; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct; Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Brown to black, smoky gray
Luster: Vitreous (glassy)

Identified June 20, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 7 on Mohs scale; Color: Brown to black, smoky gray; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct; Specific Gravity: 2.65

Formation & geological history

Formed in igneous and metamorphic rocks, particularly granite pegmatites and hydrothermal veins. The smoky color is caused by natural irradiation of aluminum-containing quartz during geological timescales.

Uses & applications

Commonly used in jewelry (faceting and cabochons), metaphysical practices, and as a popular collector specimen. Industrially, quartz is used in glassmaking and electronics.

Geological facts

The dark brown to black varieties are often called 'Cairngorm' in Scotland. Very dark, opaque smoky quartz is known as 'Morion.' It is the national gem of Scotland.

Field identification & locations

Identify by its characteristic glassy luster and smoky transparency. It will scratch glass but cannot be scratched by a steel knife. Commonly found in Brazil, USA (Colorado), and the Swiss Alps.