sedimentary

Red Sandstone

Arenite (with Iron Oxide)

Hardness: 6-7 Mohs; Color: reddish-brown to rust-red; Luster: matte/dull; Structure: Clastic, fine to medium-grained; Cleavage: none (fractures across grains); Specific Gravity: 2.2-2.8

Hardness: 6-7 Mohs
Color: reddish-brown to rust-red
Luster: matte/dull

Identified April 3, 2026More sedimentary →

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Physical properties

Hardness: 6-7 Mohs; Color: reddish-brown to rust-red; Luster: matte/dull; Structure: Clastic, fine to medium-grained; Cleavage: none (fractures across grains); Specific Gravity: 2.2-2.8

Formation & geological history

Formed through the accumulation and cementation of sand-sized mineral grains or rock fragments. The red color indicates a terrestrial deposition environment where iron-rich minerals were oxidized (rusted). Often dates from the Paleozoic or Mesozoic eras.

Uses & applications

Mostly used in construction as a building stone (dimension stone), pavers, and decorative landscaping. High-quality varieties are used for architectural facades.

Geological facts

Famous red sandstone formations include the Red Rocks of Colorado and the 'Old Red Sandstone' of Great Britain. It is a vital reservoir rock for groundwater and petroleum.

Field identification & locations

Identify in the field by its gritty, sandpaper-like texture and its tendency to rub off tiny grains of sand when scratched. Common in arid desert regions and ancient riverbeds.