sedimentary

Red sandstone

Ferruginous arkosic sandstone, likely iron-oxide cemented quartz–feldspar rock

AI-generated identification · may be incorrect

Usually Mohs 6–7 for quartz grains, but friable overall; reddish-brown from hematite/goethite, dull to earthy luster, granular texture, and no consistent cleavage. Visible bedding or fracture surfaces and occasional pale quartz/feldspar grains are typical.

Identified September 11, 2026More sedimentary →

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Physical properties

Formation & geological history

Lithified sand deposited by rivers, floodplains, dunes, or alluvial fans, then cemented by silica, calcite, or iron oxides; the exact age cannot be determined from the image. Red coloration indicates oxidation in a continental, oxygen-rich environment.

Uses & applications

Used as dimension stone, paving, aggregate, and architectural facing; attractive pieces are sold as decorative or teaching specimens, but this example is not gem-grade.

Geological facts

Iron-rich sandstone can weather into rusty surfaces and may leave a reddish streak or powder. The specimen’s irregular shape and strongly weathered/fractured texture are consistent with a natural hand specimen.

Field identification & locations

Common in continental sedimentary basins worldwide, including the western United States, India, Australia, and southern Africa. Identify it by gritty texture, visible sand grains, red iron staining, and weak reaction to dilute hydrochloric acid unless carbonate cement is present.