sedimentary

Red sandstone

Ferruginous quartz arenite (iron-oxide–cemented sandstone)

AI-generated identification · may be incorrect

Usually Mohs 6–7 because of quartz; reddish-brown, dull to slightly sandy/vitreous, fine- to medium-grained, porous, and typically lacking cleavage. The visible block appears strongly weathered, with possible bedding or lamination.

Identified September 5, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when quartz-rich sand accumulated, compacted, and was cemented by silica and iron oxides; the hematite/goethite cement produces the red color. Individual deposits range from Precambrian to recent geologic ages, depending on locality.

Uses & applications

Used as building and paving stone, aggregate, landscaping rock, and occasionally as a dimension stone; attractive polished varieties may be decorative but this specimen is mainly a field rock.

Geological facts

Red coloration generally indicates oxidation of iron during or after deposition. Sandstone commonly breaks along bedding planes and may preserve ripple marks, cross-bedding, or fossils.

Field identification & locations

Identify it by visible sand grains, gritty texture, reddish iron staining, and sedimentary layering; a streak is usually pale red to brown and it does not fizz with dilute hydrochloric acid unless carbonate cement is present. Common worldwide in arid continental and coastal basins.