sedimentary

Sandstone (Ferruginous)

Arenite with Iron Oxides

Hardness: 6-7 (Mohs); Color: Tan, brown, reddish-brown; Luster: Dull/Earthy; Crystal structure: Clastic (sand grains); Cleavage: None; Specific gravity: 2.0-2.6

Hardness: 6-7 (Mohs)
Color: Tan, brown, reddish-brown
Luster: Dull/Earthy

Identified May 3, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs); Color: Tan, brown, reddish-brown; Luster: Dull/Earthy; Crystal structure: Clastic (sand grains); Cleavage: None; Specific gravity: 2.0-2.6

Formation & geological history

Formed through the accumulation and cementation of sand-sized mineral grains or rock fragments. The brownish hue indicates the presence of iron oxide (hematite or limonite) as a cementing agent. Common in river deltas, deserts, and beach environments.

Uses & applications

Commonly used as a building material, paving stones, and for ornamental rock in landscaping. In industry, high-silica sandstone is crushed for glass making.

Geological facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. This specific specimen shows 'iron staining,' a common feature where groundwater distributes iron minerals through the porous sand structure.

Field identification & locations

Identify in the field by its gritty, sandpaper-like texture and visible layers. It is ubiquitous globally, especially in plateau regions like the American Southwest or the British Isles.