sedimentary

Banded river pebble

Likely banded sandstone or siltstone; exact identification requires testing

AI-generated identification · may be incorrect

Smooth, rounded, gray-brown pebble with fine pale laminae and a dull-to-slightly satin luster. Likely hardness about 5–7 Mohs, with no obvious cleavage; composition may include quartz, feldspar, and clay minerals.

Identified August 29, 2026More sedimentary →

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Physical properties

Formation & geological history

Water-worn in a river, beach, or glacial setting from a layered sedimentary parent rock. The original sedimentary layers may be hundreds of millions of years old, but the pebble’s rounding is much younger.

Uses & applications

Primarily a decorative or collected specimen; similar material is used as landscaping stone, aggregate, and occasionally cut or polished for ornaments.

Geological facts

The parallel bands are sedimentary laminations or compositional layers, not necessarily mineral crystals. Its rounded shape indicates prolonged abrasion during transport.

Field identification & locations

Look for fine grain, layered bands, and inability to scratch with a copper coin; quartz-rich material may scratch glass. Common in streambeds and gravel deposits worldwide; vinegar reaction would suggest carbonate cement.