sedimentary

Rounded sandstone pebble

Quartz-rich sandstone (primarily SiO₂)

AI-generated identification · may be incorrect

Hardness about 6–7 for quartz grains; tan to orange, dull earthy luster, fine granular texture, and no obvious cleavage. Its rounded shape and smooth surface indicate water or sediment abrasion.

Identified August 26, 2026More sedimentary →

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Physical properties

Hardness about 6–7 for quartz grains; tan to orange, dull earthy luster, fine granular texture, and no obvious cleavage. Its rounded shape and smooth surface indicate water or sediment abrasion.

Formation & geological history

Formed when sand was compacted and cemented, commonly by silica, iron oxides, or calcite; later rounded in a stream, beach, or glacial environment. Its exact geological age cannot be determined from the image.

Uses & applications

Used mainly as a decorative stone, landscaping aggregate, or teaching specimen; this ordinary pebble has little jewelry or industrial value.

Geological facts

The orange coloration likely comes from iron-oxide staining. A glass scratch test and close inspection of exposed grains can help distinguish sandstone from similarly colored chert or weathered granite.

Field identification & locations

Common in sedimentary basins, riverbeds, beaches, and gravel deposits worldwide. Look for visible sand grains, layered or porous texture, and weak reaction or no reaction to dilute hydrochloric acid; identification from the photograph is approximate.