sedimentary

Red Sandstone

Arenite (Ferruginous Sandstone)

Hardness: 6-7 on Mohs scale; Color: Reddish-brown due to iron oxide; Luster: Dull/Earthy; Crystal Structure: Clastic texture with visible sand-sized grains; Cleavage: None; Specific Gravity: 2.2-2.8

Hardness: 6-7 on Mohs scale
Color: Reddish-brown due to iron oxide
Luster: Dull/Earthy

Identified June 8, 2026More sedimentary →

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Physical properties

Hardness: 6-7 on Mohs scale; Color: Reddish-brown due to iron oxide; Luster: Dull/Earthy; Crystal Structure: Clastic texture with visible sand-sized grains; Cleavage: None; Specific Gravity: 2.2-2.8

Formation & geological history

Formed by the accumulation and cementation of sand-sized mineral grains or rock fragments. The red color indicates formation in an arid, oxygen-rich environment where iron minerals oxidized (rusted) within the sediment layers. Common in terrestrial environments like deserts and river floodplains.

Uses & applications

Widely used as a building material, paving stone, and in decorative landscaping. Historically important for cathedral and monument construction. High-quality varieties are used for grindstones and sculpture.

Geological facts

Red sandstone is the primary component of many famous geological landmarks, such as the Grand Canyon in the USA and the 'Red Rocks' of Sedona. It often preserves fossils and ripple marks from ancient water or wind currents.

Field identification & locations

Identify in the field by its gritty texture (feels like sandpaper) and visible layers or bedding planes. It is commonly found in basins and plateaus globally. Collectors look for pieces with unique cross-bedding or mineral inclusions.