sedimentary

Rounded sandstone pebble

Quartz-rich sandstone, likely ferruginous or arkosic

AI-generated identification · may be incorrect

Tan-orange, matte to slightly earthy luster, fine-grained and rounded by abrasion; predominantly quartz with feldspar and iron-oxide cement. Estimated hardness 6–7 for grains, but the friable cement may scratch or crumble; no visible cleavage or crystals.

Identified August 26, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when sand was compacted and cemented, commonly by silica, calcite, or iron oxides, then weathered into a pebble by water or glacial transport. Its exact geological age cannot be determined from the photograph.

Uses & applications

Used as aggregate, paving, building stone, and occasionally as a decorative or educational specimen; this small piece has little commercial value.

Geological facts

The orange coloration commonly reflects hematite or limonite coatings between quartz grains. Its smooth shape indicates prolonged transport or tumbling rather than crystal growth.

Field identification & locations

Look for visible sand grains, possible layering, and gritty texture; sandstone commonly occurs in sedimentary basins, riverbeds, beaches, and glacial deposits. A hand lens and dilute hydrochloric acid can help distinguish carbonate cement, though no fizz is expected for quartz-rich sandstone.