sedimentary

Rounded sandstone pebble

Quartz-rich sandstone, likely ferruginous or arkosic sandstone

AI-generated identification · may be incorrect

Hardness about 6–7; tan to brown, fine-grained, dull to slightly gritty luster, with no visible cleavage. Rounded shape and smooth surface indicate abrasion by water or sediment transport; exact composition cannot be confirmed from the photograph.

Identified September 7, 2026More sedimentary →

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Physical properties

Formation & geological history

Lithified sand compacted and cemented, probably with silica, iron oxide, or calcium carbonate; likely formed millions to hundreds of millions of years ago, depending on its source formation. Its rounded form developed in a stream, beach, or glacial environment.

Uses & applications

Common sandstone is used as building stone, paving, aggregate, and landscaping material; attractive pieces may be collected but are usually low-value.

Geological facts

The brown coloration commonly comes from iron-oxide coatings or cement. A scratch test, acid test, and fresh broken surface would distinguish sandstone from weathered quartzite or fine-grained volcanic rock.

Field identification & locations

Look for visible sand grains and weak layering; sandstone typically feels slightly abrasive and may shed grains when scratched. Common worldwide, especially in sedimentary basins, riverbeds, beaches, and glacial deposits.