sedimentary

Red Sandstone

Arenite (SiO2 with Fe2O3)

Hardness: 6-7 (Mohs scale); Color: Red, reddish-brown, or orange due to iron oxide; Luster: Dull/Earthy; Structure: Granular/Clastic; Cleavage: None; Specific Gravity: 2.2-2.8

Hardness: 6-7 (Mohs scale)
Color: Red, reddish-brown, or orange due to iron oxide
Luster: Dull/Earthy

Identified July 19, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs scale); Color: Red, reddish-brown, or orange due to iron oxide; Luster: Dull/Earthy; Structure: Granular/Clastic; Cleavage: None; Specific Gravity: 2.2-2.8

Formation & geological history

Formed over millions of years by the accumulation and cementation of sand-sized mineral particles or rock fragments. The red color indicates formation in an oxygen-rich environment where iron minerals oxidized.

Uses & applications

Commonly used as a building material, paving stone, and in decorative landscaping. Also serves as a crucial aquifer for groundwater storage.

Geological facts

Red sandstone formations like the Old Red Sandstone or the Navajo Sandstone are famous for creating iconic landscapes like the Grand Canyon and Sedona's Red Rocks.

Field identification & locations

Identify by its gritty, sandpaper-like feel and visible grains. Often found in desert environments or ancient riverbeds. Testing with a hand lens reveals the distinct sand grains cemented together.