mineral

Brown quartz-rich stone, possibly smoky quartz or quartzite

Quartz (SiO₂), potentially in a quartzite or silica-rich matrix

AI-generated identification · may be incorrect

Appears brown-gray, opaque to translucent, with a dull to vitreous luster and irregular fracture; quartz hardness is 7 on the Mohs scale, with no cleavage and specific gravity about 2.65.

Identified August 11, 2026More mineral →

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Physical properties

Appears brown-gray, opaque to translucent, with a dull to vitreous luster and irregular fracture; quartz hardness is 7 on the Mohs scale, with no cleavage and specific gravity about 2.65.

Formation & geological history

Likely formed through crystallization of silica-rich fluids or metamorphism of sandstone into quartzite; its exact geological age and origin cannot be determined from the photograph.

Uses & applications

Quartz is used in glass, ceramics, electronics, abrasives, and countertops; attractive pieces may be collected or used as cabochons, though this specimen appears too small and irregular for high-value jewelry.

Geological facts

The brown color may result from iron staining, inclusions, or radiation-related smoky coloration. A steel knife should not scratch quartz, while quartz can scratch ordinary glass.

Field identification & locations

Common worldwide, including Brazil, the United States, Madagascar, and Europe. Confirm identification with a hardness test, glass-scratch test, streak, and inspection for quartz grains or crystalline faces.