mineral

Tumbled smoky quartz

Quartz (SiO₂), brown-gray smoky variety

AI-generated identification · may be incorrect

Mohs hardness 7; translucent brown to gray body with vitreous luster and conchoidal fracture. Trigonal crystal structure, no cleavage; specific gravity about 2.65.

Identified August 17, 2026More mineral →

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Physical properties

Mohs hardness 7; translucent brown to gray body with vitreous luster and conchoidal fracture. Trigonal crystal structure, no cleavage; specific gravity about 2.65.

Formation & geological history

Forms in silica-rich hydrothermal veins, pegmatites, and cavities, commonly acquiring its smoky color from natural irradiation of aluminum-bearing quartz. Specimen age depends on its host deposit, often millions to hundreds of millions of years.

Uses & applications

Used as a collector specimen, carving material, and occasional gemstone; quartz is also essential in glass, electronics, abrasives, and construction aggregate.

Geological facts

The pictured piece appears naturally fractured and possibly lightly polished; its gray-brown translucency is consistent with smoky quartz, though similar chalcedony or ordinary quartz is possible without testing.

Field identification & locations

Identify by hardness, glassy luster, conchoidal fracture, and inability to scratch it with a steel knife; it should scratch glass. Common localities include Brazil, Madagascar, Switzerland, the United States, and Spain.