sedimentary

Tumbled beach pebble (likely quartz-rich sandstone or chert)

Indeterminate lithic clast; likely quartz (SiO₂)-rich sandstone/chert

AI-generated identification · may be incorrect

Smooth, naturally rounded, matte tan-gray surface with very fine grain and no visible crystals; estimated Mohs hardness 5–7, depending on composition. Likely subvitreous to earthy luster, massive texture, and no obvious cleavage.

Identified September 6, 2026More sedimentary →

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Physical properties

Formation & geological history

Rounded by prolonged wave or stream abrasion; the original sedimentary material may be millions to hundreds of millions of years old, but its exact age cannot be determined visually. The unusually smooth shape suggests beach or river transport, possibly enhanced by tumbling.

Uses & applications

Suitable as a decorative pebble, craft material, paperweight, or aquarium/landscaping stone if composition and cleanliness are verified. It has little commercial value unless distinctive provenance or unusual composition is established.

Geological facts

The image does not show diagnostic features sufficient for a precise species identification; it could also be a weathered fine-grained volcanic or metamorphic fragment. A streak, acid, hardness, and specific-gravity test would narrow the identification.

Field identification & locations

Common in beaches, river gravels, and glacial deposits. Check for reaction to vinegar or dilute hydrochloric acid, glass-scratching ability, grain texture, and a fresh broken surface; avoid destructive testing if it is a keepsake.