sedimentary

Red Sandstone

Arenite (Ferruginous Sandstone)

Hardness: 6-7 Mohs; Color: reddish-brown due to iron oxide; Luster: matte/earthy; Crystal Structure: Clastic (sand-sized grains); Specific Gravity: 2.2-2.8

Hardness: 6-7 Mohs
Color: reddish-brown due to iron oxide
Luster: matte/earthy

Identified July 9, 2026More sedimentary →

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Physical properties

Hardness: 6-7 Mohs; Color: reddish-brown due to iron oxide; Luster: matte/earthy; Crystal Structure: Clastic (sand-sized grains); Specific Gravity: 2.2-2.8

Formation & geological history

Formed by the accumulation and cementation of mineral particles (sand) over millions of years, typically in desert or river environments. The red color is caused by the oxidation of iron minerals like hematite.

Uses & applications

Historically used as a building material for iconic architecture, paving, and occasionally for decorative carvings or as an abrasive.

Geological facts

Red sandstone is the primary material of the famous 'red rocks' in places like Sedona, Arizona, and the Grand Canyon. It can preserve fossils and ancient ripple marks from prehistoric water bodies.

Field identification & locations

Identify by its gritty texture (feels like sandpaper) and distinct layering. Common in arid regions and sedimentary basins worldwide. It will not fizz with acid unless it has a calcitic cement.