mineral

Tumbled smoky quartz (likely)

Quartz, SiO₂; smoky variety colored by irradiation-related defects

AI-generated identification · may be incorrect

Translucent brown-to-gray, vitreous luster, irregular conchoidal fracture, no visible cleavage, Mohs hardness 7, specific gravity about 2.65. The rounded edges indicate tumbling or polishing; internal cloudiness may reflect inclusions or fractures.

Identified September 12, 2026More mineral →

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Physical properties

Formation & geological history

Forms in hydrothermal veins, pegmatites, and cavities of igneous rocks, commonly crystallizing from silica-rich fluids over millions of years. Brown coloration results mainly from natural radiation acting on aluminum impurities.

Uses & applications

Used as an inexpensive lapidary and ornamental stone, jewelry component, meditation stone, and mineral specimen; generally unsuitable for construction because of its small size.

Geological facts

The photograph supports a quartz identification but cannot distinguish smoky quartz confidently from brown chalcedony, glass, or another dark translucent stone without tests. Quartz is abundant and chemically resistant.

Field identification & locations

Check for glassy luster, hardness sufficient to scratch ordinary glass, and lack of cleavage; a steel file should not easily scratch it. Common sources include Brazil, Madagascar, Switzerland, the United States, and Scotland.