sedimentary

Red Sandstone

Arenite (Ferruginous Sandstone)

Hardness: 6-7 Mohs; Color: Dull red to brownish-red; Luster: Dull/Earthy; Structure: Clastic, fine-grained; Cleavage: None; Specific Gravity: 2.2-2.8.

Hardness: 6-7 Mohs
Color: Dull red to brownish-red
Luster: Dull/Earthy

Identified May 20, 2026More sedimentary →

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Physical properties

Hardness: 6-7 Mohs; Color: Dull red to brownish-red; Luster: Dull/Earthy; Structure: Clastic, fine-grained; Cleavage: None; Specific Gravity: 2.2-2.8.

Formation & geological history

Formed by the accumulation and lithification of sand-sized mineral grains, predominantly quartz. The red color is derived from the oxidation of iron-bearing minerals (hematite) during the diagenesis process, often in arid or fluviatile environments.

Uses & applications

Commonly used in construction as a building stone (brownstone), in landscaping, as a source for glass-making sand, and occasionally as a base material for road construction.

Geological facts

Red desert sandstones, like those in the American Southwest or the Old Red Sandstone of Northern Europe, preserve ancient terrestrial environments. The red pigmentation often indicates deposition in oxygen-rich, non-marine environments.

Field identification & locations

Identified by its gritty 'sandpaper' feel and visible grain structure. Look for bedding planes and use a hand lens to see mineral grains. Commonly found in basins and old river beds worldwide.