sedimentary

Red Sandstone

Ferruginous Sandstone (SiO2 with Fe2O3)

AI-generated identification · may be incorrect

Hardness: 6-7 (Mohs); Color: terracotta, red, or reddish-brown; Luster: dull to earthy; Structure: clastic; Cleavage: none; Texture: gritty, like sandpaper.

Hardness: 6-7 (Mohs)
Color: terracotta, red, or reddish-brown
Luster: dull to earthy

Identified July 17, 2026More sedimentary →

Explore Red Sandstone in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 6-7 (Mohs); Color: terracotta, red, or reddish-brown; Luster: dull to earthy; Structure: clastic; Cleavage: none; Texture: gritty, like sandpaper.

Formation & geological history

Formed by the accumulation of sand-sized mineral grains or rock fragments, cemented together by silica, calcium carbonate, or iron oxide. The red color indicates formation in an oxygen-rich environment where iron minerals oxidized.

Uses & applications

Commonly used as a building material for facades, pavers, and retaining walls; also popular for decorative landscaping and as an abrasive in industrial applications.

Geological facts

Red sandstone formations, such as the Old Red Sandstone, are famous for preserving early vertebrate fossils. It is the primary material used in the construction of iconic structures like the Red Fort in India and Petra in Jordan.

Field identification & locations

Identified by its gritty texture and distinct layering or cross-bedding. In the field, look for consistent grain sizes and the ability to rub small grains of sand off the surface with a finger.