sedimentary

Rounded quartz-rich pebble

Likely quartz sandstone or quartzite; visual identification is uncertain

AI-generated identification · may be incorrect

Tan-gray, fine-grained, dull to weakly sparkling surface with rounded water-worn edges; likely Mohs 6–7 if quartz-rich, with no obvious cleavage. Specific gravity approximately 2.6–2.7.

Identified September 5, 2026More sedimentary →

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Physical properties

Tan-gray, fine-grained, dull to weakly sparkling surface with rounded water-worn edges; likely Mohs 6–7 if quartz-rich, with no obvious cleavage. Specific gravity approximately 2.6–2.7.

Formation & geological history

Possibly sandstone cemented from quartz sand, or metamorphosed sandstone (quartzite); commonly formed in ancient sedimentary basins and later rounded by stream or beach transport. Exact age and identity require hardness, acid, and thin-section testing.

Uses & applications

Usually a landscaping or collected pebble; quartzite can be used as aggregate, building stone, and decorative stone. This specimen has little jewelry value unless it proves to be an attractive distinctive variety.

Geological facts

The granular texture and muted color suggest quartz-rich rock rather than a single crystal mineral. A glass-scratch test and examination of broken surfaces can help distinguish sandstone from quartzite.

Field identification & locations

Common in river gravels, beaches, glacial deposits, and weathered outcrops worldwide. Quartzite feels dense and sugary-crystalline, whereas sandstone more readily shows individual sand grains and may scratch less consistently.