sedimentary

Sandstone

Arenite (Clastic Sedimentary Rock)

Hardness: 6-7 on Mohs scale; Color: Tan, brown, yellow, and reddish-brown due to iron oxide; Luster: Dull or earthy; Crystal structure: Granular (composed of sand-sized mineral particles or rock fragments); Cleavage: None; Specific gravity: 2.2-2.8

Hardness: 6-7 on Mohs scale
Color: Tan, brown, yellow, and reddish-brown due to iron oxide
Luster: Dull or earthy

Identified July 19, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed by the accumulation of sand-sized grains (mostly quartz and feldspar) in environments like deserts, river deltas, or beaches. Over millions of years, these layers are compressed and cemented together by minerals like silica, calcium carbonate, or iron oxide.

Uses & applications

Used extensively in construction as a building stone, in the manufacture of glass, and for landscaping. In some regions, certain types serve as high-quality grindstones for sharpening tools.

Geological facts

Sandstone is highly porous, making it an excellent aquifer for groundwater storage. Red sandstone, like that found in the American Southwest or the Old Red Sandstone of Britain, gets its color from hematite (iron oxide).

Field identification & locations

Identify in the field by its gritty texture (feels like sandpaper) and visible layering (bedding). It is found globally in sedimentary basins. Collectors often look for fossil inclusions or unique 'liesegang' color banding.