sedimentary

Red sandstone pebble

Ferruginous sandstone, chiefly quartz (SiO₂) cemented by iron oxides

AI-generated identification · may be incorrect

Typically Mohs hardness 6–7 for quartz grains, reddish-brown color, dull to earthy luster, and granular texture; it appears naturally rounded and weathered. The surface shows fine pores, pits, and likely iron-stained cement.

Identified September 8, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when quartz-rich sand was compacted and cemented, with iron oxides producing the red color; the exact geological age cannot be determined from the image. Rounding indicates transport by water, waves, or glacial action.

Uses & applications

Used as building and paving stone when sufficiently durable, while small pieces are mainly decorative, educational, or collectible. Common specimens generally have little commercial value.

Geological facts

The red coloration is usually caused by hematite or hydrated iron oxides coating quartz grains rather than abundant red minerals. Its smooth shape is a transport feature, not crystal growth.

Field identification & locations

Common in riverbeds, beaches, deserts, and eroded sandstone formations; identify it by visible sand grains, earthy red coloration, and lack of cleavage or large crystals. A hand lens and dilute acid test can help distinguish it from limestone, though acid reaction is usually absent.