sedimentary

Red sandstone

Quartz-rich sandstone, commonly ferruginous (Fe-oxide stained)

AI-generated identification · may be incorrect

Typically Mohs 6–7 for quartz grains; reddish-brown, dull to earthy luster, and granular texture. Individual grains and possible bedding are visible; cleavage is absent, with variable porosity and specific gravity around 2.2–2.7.

Identified August 8, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when sand—mostly quartz—was deposited, compacted, and cemented, often in rivers, deserts, or coastal environments. Its red color comes from iron-oxide coatings; age depends on locality and may range from ancient to relatively young.

Uses & applications

Used as building stone, paving, landscaping aggregate, and architectural sandstone; attractive pieces may be collected, though this small specimen has limited commercial value.

Geological facts

Iron oxidation produces the characteristic red coloration, while weaker cement can make sandstone weather into rounded fragments.

Field identification & locations

Identify it by gritty quartz grains, visible sedimentary layering or texture, and reddish iron staining; it should not fizz with dilute hydrochloric acid unless carbonate cement is present. Common worldwide, especially in arid sedimentary basins.