sedimentary

Sandstone (Ferruginous)

Arenite with Iron Oxides

Hardness: 6-7 on Mohs scale; Color: Tan to reddish-brown due to iron oxidation; Luster: Dull/Earthy; Crystal Structure: Granular/Clastic; Cleavage: None; Specific Gravity: 2.2-2.8

Hardness: 6-7 on Mohs scale
Color: Tan to reddish-brown due to iron oxidation
Luster: Dull/Earthy

Identified May 8, 2026More sedimentary →

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Physical properties

Hardness: 6-7 on Mohs scale; Color: Tan to reddish-brown due to iron oxidation; Luster: Dull/Earthy; Crystal Structure: Granular/Clastic; 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 brownish hue indicates exposure to oxygen and water, causing iron-rich minerals to oxidize (rust).

Uses & applications

Commonly used as a building material, paving stone, and in the production of glass or as a source of industrial sand.

Geological facts

Sandstone makes up approximately 20 to 25 percent of all sedimentary rocks on Earth and is a primary reservoir for groundwater, oil, and gas due to its porosity.

Field identification & locations

Identify by its gritty, sandpaper-like texture and visible layered bedding. It is found globally in deserts, river basins, and coastal areas. Collectors look for unique banding patterns like Liesegang rings.