mineral

Smoky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Gray to brownish-black; Luster: Vitreous; Crystal Structure: Hexagonal; Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Gray to brownish-black
Luster: Vitreous

Identified June 2, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Gray to brownish-black; Luster: Vitreous; Crystal Structure: Hexagonal; Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65

Formation & geological history

Formed in igneous and metamorphic rocks, particularly pegmatites and hydrothermal veins. Coloration results from free silicon formed from silicon dioxide by natural irradiation.

Uses & applications

Used in jewelry, ornamental carvings, and as a popular collector's mineral. Historically used for one of the first types of sunglasses in China.

Geological facts

The brown-to-black color is caused by the natural irradiation of aluminum-rich quartz. Darker varieties that are almost opaque are sometimes referred to as 'Morion'.

Field identification & locations

Identify by its hardness (scratches glass), lack of cleavage, and translucent brown/gray tint. Common in mountain ranges like the Alps, Appalachians, and granitic terrains worldwide.