mineral

Likely tumbled smoky quartz

Smoky quartz (SiO₂), possibly iron- or radiation-colored quartz

AI-generated identification · may be incorrect

Brown to dark smoky translucent appearance with vitreous luster and irregular conchoidal fractures; Mohs hardness 7, hexagonal crystal structure, no cleavage, specific gravity about 2.65. The rounded, glossy surface indicates tumbling or water wear.

Identified September 4, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallizes from silica-rich hydrothermal fluids and pegmatites, commonly in cavities of igneous rocks; smoky coloration develops from irradiation affecting aluminum impurities. Quartz ranges from Precambrian to recent in age.

Uses & applications

Used as a collector specimen, ornamental stone, and occasionally in jewelry; quality depends on transparency, color, and absence of fractures.

Geological facts

The photograph does not show diagnostic crystal faces, so dark brown quartz is a best visual identification; it could also be another brown, silica-rich material such as chert or glassy slag.

Field identification & locations

Test with a steel file or knife: genuine quartz resists scratching, while glass-like imitations may be softer or show bubbles. Common sources include Brazil, Madagascar, Switzerland, Colorado, and New Hampshire.