mineral

Tumbled smoky quartz (probable)

Quartz, silicon dioxide (SiO₂), colored by radiation-related aluminum defects

AI-generated identification · may be incorrect

Small polished pebble with translucent smoky-gray to brown color and vitreous luster; quartz hardness is 7 Mohs, has a hexagonal crystal structure, no cleavage, conchoidal fracture, and specific gravity about 2.65.

Identified August 15, 2026More mineral →

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Physical properties

Formation & geological history

Forms mainly in granitic pegmatites, hydrothermal veins, and cavities when silica-rich fluids crystallize; smoky coloration develops from natural irradiation. Exact age and locality cannot be determined from the photograph.

Uses & applications

Used as an ornamental and lapidary material, in jewelry, carvings, and mineral collections; quartz also has major industrial uses in glass, electronics, and engineered stone.

Geological facts

The rounded surface indicates tumbling or polishing rather than natural crystal faces. Color can range from pale gray to nearly black (“morion”).

Field identification & locations

Common localities include Brazil, Switzerland, Scotland, Madagascar, and the United States. Confirm with hardness testing, glass-scratching ability, and absence of cleavage; visual identification is not definitive because other dark minerals can resemble it.