gemstone

Smoky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale. Color: Smoky brownish-gray to deep translucent dark brown/black. Luster: Vitreous (glassy). Crystal structure: Hexagonal (Trigonal). Cleavage: None, exhibits conchoidal fracture. Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Smoky brownish-gray to deep translucent dark brown/black
Luster: Vitreous (glassy)

Identified July 28, 2026More gemstone →

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Physical properties

Formation & geological history

Forms in igneous and metamorphic rocks, particularly pegmatites, hydrothermal veins, and alpine-type fissures. The distinctive dark smoky color is caused by natural radiation acting on trace aluminum impurities within the crystal structure.

Uses & applications

Faceted as a gemstone for fine jewelry, pendants, beads, and ring stones. Also popular among mineral collectors, energy healers, and for decorative carvings.

Geological facts

Smoky quartz was used in 12th-century China to make primitive sunglasses in the form of flat smoked quartz lenses. It is also the national gem of Scotland, where it is known as Cairngorm.

Field identification & locations

Identified by its signature translucent smoky brown-to-black color, high hardness (scratches glass), and glassy luster. Commonly found in Brazil, Madagascar, the US (Colorado), Switzerland, and Scotland.