mineral

Likely tumbled brown agate

Microcrystalline quartz (SiO₂), chalcedony variety; precise identification is uncertain from the photo

AI-generated identification · may be incorrect

Small, rounded, opaque-to-translucent brown pebble with a subdued polish. Quartz hardness is 7 Mohs; trigonal crystal structure, vitreous to waxy luster, no cleavage, and specific gravity about 2.6.

Identified October 12, 2026More mineral →

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Physical properties

Small, rounded, opaque-to-translucent brown pebble with a subdued polish. Quartz hardness is 7 Mohs; trigonal crystal structure, vitreous to waxy luster, no cleavage, and specific gravity about 2.6.

Formation & geological history

Agate forms as silica-rich fluids fill cavities in volcanic rock and deposit chalcedony in layers; deposits range from ancient to geologically recent. The pebble appears tumbled or naturally water-worn.

Uses & applications

Used for jewelry, ornaments, and lapidary collections; agate is also used for small decorative objects and occasionally precision components.

Geological facts

Agate is identified by its chalcedony composition and often by visible banding, though bands are not apparent here.

Field identification & locations

Look for waxy luster, hardness sufficient to scratch glass, and any fine concentric bands when viewed in strong light. Agates occur worldwide, including Brazil, Uruguay, India, and the western United States.