sedimentary

Sandstone

Arenite (SiO2 based)

Hardness: 6-7 Mohs; Color: Brown, reddish-brown, tan; Luster: Dull, earthy; Crystal structure: Granular/clastic; Specific gravity: 2.2-2.8; Feel: Gritty like sandpaper.

Hardness: 6-7 Mohs
Color: Brown, reddish-brown, tan
Luster: Dull, earthy

Identified July 3, 2026More sedimentary →

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Physical properties

Hardness: 6-7 Mohs; Color: Brown, reddish-brown, tan; Luster: Dull, earthy; Crystal structure: Granular/clastic; Specific gravity: 2.2-2.8; Feel: Gritty like sandpaper.

Formation & geological history

Formed over millions of years by the accumulation and cementation of sand-sized mineral grains (usually quartz) in environments like deserts, river beds, or beaches.

Uses & applications

Widely used as a building material, paving stone, and in the production of glass (if high silica content). Historically used for grindstones.

Geological facts

Sandstone can preserve fossil footprints and ripple marks from ancient water bodies. Red varieties get their color from iron oxide (rust) coating the grains.

Field identification & locations

Identify by its gritty texture and visible sand grains. It is extremely common in arid regions and canyonlands. Test by rubbing against a harder surface to see if grains dislodge.