mineral

Smoky Quartz (with inclusions)

Silicon Dioxide (SiO2)

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

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

Identified April 6, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed through the cooling of silica-rich magma or from hydrothermal veins. The smoky color is caused by natural irradiation of trace aluminum impurities within the crystal structure, typically over millions of years.

Uses & applications

Used as a gemstone in jewelry, decorative carvings, and in metaphysical practices. Industrially, high-purity quartz is used in electronics and glass manufacturing.

Geological facts

Smoky quartz is the national gem of Scotland, where it is often referred to as 'Cairngorm' after the mountains where it is found. Its color can range from a light smoke-gray to an almost opaque black (called Morion).

Field identification & locations

Identify by its hardness (will scratch glass), glassy luster, and the presence of brownish/grayish 'smoke' colors throughout the crystal. Common in granite pegmatites and metamorphic rocks worldwide.

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