sedimentary

Weathered brown river pebble, likely sandstone or iron-rich quartzite

Indeterminate; probable quartz-rich sandstone (quartz and iron-oxide cement)

AI-generated identification · may be incorrect

Fine-grained, tan-brown, dull to slightly earthy luster, rounded by abrasion, with no visible crystals or cleavage. Likely Mohs hardness about 5–7, depending on cementation; specific gravity roughly 2.5–2.7.

Identified September 2, 2026More sedimentary →

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Physical properties

Formation & geological history

Probably a naturally weathered and water-rounded clast derived from sedimentary or metamorphic bedrock; iron oxides produce the brown coloration. Exact age and source cannot be determined from the photograph.

Uses & applications

Commonly used as landscaping stone, aggregate, or a teaching/collecting specimen; this unremarkable pebble has little jewelry value.

Geological facts

The rounded shape indicates prolonged transport in a stream, beach, or glacial environment. A glass-scratch test and dilute hydrochloric-acid test can help distinguish quartz-rich rock from calcareous stone.

Field identification & locations

Common in streambeds and gravel deposits worldwide. Look for gritty sand-sized grains and layered texture for sandstone; a harder, sparkly, fused texture suggests quartzite; fizzing with acid indicates carbonate rock instead.