mineral

Tumbled smoky quartz

Quartz, silicon dioxide (SiO₂), smoky variety colored by irradiation-related defects

AI-generated identification · may be incorrect

Mohs hardness 7; translucent gray-brown to smoky black, vitreous luster, commonly massive rather than visibly crystalline, with indistinct cleavage and conchoidal fracture; specific gravity about 2.65.

Identified August 27, 2026More mineral →

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Physical properties

Formation & geological history

Forms in silica-rich hydrothermal veins, pegmatites, and cavities of igneous rocks, where natural radiation creates its smoky color. Individual specimens may range from Paleozoic to recent geologic ages.

Uses & applications

Used as an ornamental and lapidary stone, for tumbled stones, carvings, jewelry, and mineral collections; it has little industrial value compared with ordinary quartz.

Geological facts

The rounded shape and glossy surface indicate mechanical tumbling and polishing. Color can fade with strong heat or sunlight, and very dark material may be artificially irradiated.

Field identification & locations

Identify it by hardness, glassy luster, translucent smoky coloration, and lack of obvious cleavage; it should scratch window glass but not be scratched by a steel knife. Common sources include Brazil, Madagascar, Switzerland, the United States, and Spain.