sedimentary

Rounded river pebble

Lithic sandstone or fine-grained volcanic/metamorphic pebble; exact identity requires testing

AI-generated identification · may be incorrect

Fine-grained, brown-gray, subrounded and water-worn with a dull-to-slightly earthy luster; likely hardness about 5–7 Mohs, no visible crystals or cleavage, and moderate density. The mottled dark and pale areas may reflect different minerals or weathering.

Identified August 16, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from pre-existing rock and rounded by transport in a stream, beach, or glacial environment; its original rock may be millions to billions of years old, but the pebble’s current shape developed during recent erosion.

Uses & applications

Usually a common natural pebble with decorative, landscaping, craft, or educational value; not typically suitable for jewelry unless it has unusual composition or provenance.

Geological facts

The image alone cannot reliably distinguish sandstone from basalt, quartzite, or another fine-grained rock. A streak, acid, hardness, and close-grain examination would improve identification.

Field identification & locations

Common in riverbeds, beaches, gravel deposits, and glacial till. Look for grain texture, reaction to dilute hydrochloric acid, glass-scratching ability, and whether a steel file scratches it; avoid destructive tests if collected.