sedimentary

Sandstone (Ferruginous)

Arenite with Iron-Oxide Cement

AI-generated identification · may be incorrect

Hardness: 6-7 (Mohs scale); Color: Brown, reddish-brown, tan; Luster: Dull to earthy; Crystal structure: Clastic (grainy texture); Cleavage: None; Specific gravity: 2.2-2.8.

Hardness: 6-7 (Mohs scale)
Color: Brown, reddish-brown, tan
Luster: Dull to earthy

Identified April 7, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs scale); Color: Brown, reddish-brown, tan; Luster: Dull to earthy; Crystal structure: Clastic (grainy texture); Cleavage: None; Specific gravity: 2.2-2.8.

Formation & geological history

Formed by the accumulation and cementation of sand-sized silicate grains (mostly quartz). The dark reddish-brown color indicates 'ferruginous' sandstone, where iron oxide (hematite or limonite) acts as the cementing agent. These typically form in terrestrial arid environments or river beds.

Uses & applications

Used primarily as a building material, paving stone, and in glass manufacturing or metal casting if high in silica. Iron-rich varieties are occasionally used for landscaping.

Geological facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. This specific variety's color is the same chemistry that gives the planet Mars its reddish hue.