sedimentary

Red Sandstone

Arenite (with Iron Oxide / Hematite cementation)

AI-generated identification · may be incorrect

Hardness: 6-7 on Mohs scale (due to quartz content); Color: Red, reddish-brown, or brick-red; Luster: Dull/Earthy; Crystal structure: Clastic (composed of sand-sized grains); Cleavage: None; Specific Gravity: 2.2-2.8

Hardness: 6-7 on Mohs scale (due to quartz content)
Color: Red, reddish-brown, or brick-red
Luster: Dull/Earthy

Identified February 24, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed by the accumulation and cementation of sand-sized minerals or rock grains. The red color suggests deposition in an oxygen-rich environment (terrestrial) where iron-bearing minerals oxidized into hematite. Often associated with ancient desert, river, or coastal environments.

Uses & applications

Commonly used in construction as a building stone (dimension stone), pavers, and decorative landscaping. High-quality varieties are used in historical architecture and monuments.

Geological facts

Famous for forming the 'Red Rocks' of the American Southwest. The red pigment is actually a very thin coating of iron oxide on the individual sand grains rather than the grains themselves being red.

Field identification & locations

Identify by its gritty, sandpaper-like texture and its visible sand grains. Found globally in continental sedimentary basins. Collectors look for unique 'Liesegang rings' or fossil inclusions within the layers.