sedimentary

Sandstone (Ferruginous)

Arenite (Fe-rich)

Hardness: 6-7 (Mohs); Color: Reddish-orange, tan, or ochre due to iron oxide; Luster: Dull/Earthy; Structure: Clastic, fine to medium-grained; Cleavage: None; Specific Gravity: 2.2-2.8

Hardness: 6-7 (Mohs)
Color: Reddish-orange, tan, or ochre due to iron oxide
Luster: Dull/Earthy

Identified May 12, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs); Color: Reddish-orange, tan, or ochre due to iron oxide; Luster: Dull/Earthy; Structure: Clastic, fine to medium-grained; Cleavage: None; Specific Gravity: 2.2-2.8

Formation & geological history

Formed through the accumulation and cementation of sand-sized mineral grains or rock fragments. The reddish color indicates deposition in an oxidizing environment (terrestrial or shallow marine) where iron-bearing minerals like hematite act as the cementing agent.

Uses & applications

Primarily used as a building material, decorative stone, and in the manufacturing of glass and grindstones. Also a significant reservoir for groundwater and petroleum.

Geological facts

Sandstone accounts for roughly 20-25% of all sedimentary rocks on Earth. The iconic red rocks of the American Southwest, such as those in the Grand Canyon and Zion National Park, are massive sandstone formations.

Field identification & locations

Identify in the field by its gritty, sandpaper-like feel and visible grains. Often displays bedding planes or cross-stratification. Common in desert environments and river basins.