sedimentary

Rounded river pebble (likely weathered sandstone or chert)

Indeterminate clastic sedimentary rock; possible quartz-rich sandstone

AI-generated identification · may be incorrect

Tan-brown, fine-grained, dull to earthy luster, with rounded water-worn shape and subtle mottling. Estimated hardness 5–7 Mohs; no visible cleavage or crystals; composition may include quartz, feldspar, and iron oxides.

Identified September 15, 2026More sedimentary →

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Physical properties

Formation & geological history

Likely formed from lithified sand or siliceous sediment, then rounded by stream or beach abrasion. Exact geological age and formation environment cannot be determined from the photograph.

Uses & applications

Primarily a natural collectible, landscaping stone, or craft material; not identifiable as a gem-grade specimen or commercially significant building stone from the image.

Geological facts

The smooth oval shape reflects prolonged transport and abrasion by moving water or waves. Brown coloration commonly results from iron-oxide staining.

Field identification & locations

Test a fresh edge for texture: sandstone feels granular and may scratch glass weakly, whereas chert is smoother and scratches glass readily. Common in streambeds, beaches, and gravel deposits; acid testing and a fresh fracture would improve identification.