sedimentary

Rounded river pebble, likely quartz-rich sandstone or weathered quartzite

Tentative: quartz arenite (sandstone) or quartzite; chiefly SiO₂

AI-generated identification · may be incorrect

Tan-brown, opaque, fine-grained, and matte to slightly waxy, with a natural fracture/seam and water-worn shape. Estimated hardness 6–7 Mohs; no visible cleavage; specific gravity roughly 2.6–2.7.

Identified August 15, 2026More sedimentary →

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Physical properties

Tan-brown, opaque, fine-grained, and matte to slightly waxy, with a natural fracture/seam and water-worn shape. Estimated hardness 6–7 Mohs; no visible cleavage; specific gravity roughly 2.6–2.7.

Formation & geological history

Likely formed from compacted quartz sand (sandstone) or metamorphosed sandstone (quartzite), then rounded by stream or shoreline abrasion. Its exact geological age and identity cannot be determined reliably from the photograph alone.

Uses & applications

Commonly used as landscaping stone, aggregate, and decorative pebble; generally little jewelry or collector value unless unusually patterned or from a notable locality.

Geological facts

The smooth form indicates prolonged transport or abrasion. A glass-scratch test, streak, close inspection of grain boundaries, and dilute acid test can help distinguish quartzite from carbonate rock.

Field identification & locations

Common in river gravels, beaches, and glacial deposits worldwide; quartz-rich specimens resist weathering and commonly remain as rounded residual pebbles. It should scratch glass and show no reaction to dilute hydrochloric acid.