sedimentary

Red sandstone

Ferruginous quartz arenite (iron-oxide-cemented sandstone)

AI-generated identification · may be incorrect

Typically 6–7 Mohs for quartz grains, reddish-brown from hematite or limonite, dull to earthy luster, and granular texture; bedding or lamination may be visible. It is usually porous and lacks cleavage, with specific gravity around 2.2–2.7.

Identified September 11, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when sand-sized quartz and rock fragments accumulated, compacted, and cemented, with iron oxides producing the red color. Red-bed sandstones range from Precambrian to Recent, commonly forming in oxidizing deserts, river plains, and coastal environments.

Uses & applications

Used as building stone, paving, aggregate, and decorative stone; attractive pieces are collected, though this specimen has limited gem value.

Geological facts

The red coloration records oxidation of iron during or after deposition. Iron-rich sandstone can weather into distinctive rusty surfaces and may preserve ripple marks, mud cracks, or fossils.

Field identification & locations

Identify it by its gritty feel, visible sand grains, reddish color, and possible layering; a steel nail may scratch individual grains only weakly. Common worldwide, including Utah, Arizona, Colorado, India, and the United Kingdom.