sedimentary

Sandstone (River Rock)

Arenite (SiO2 principal component)

AI-generated identification · may be incorrect

Hardness: 6-7 Mohs; Color: Brown, tan, or grey; Luster: Dull to earthy; Texture: Granular and gritty; Cleavage: None; Specific Gravity: 2.2-2.8

Hardness: 6-7 Mohs
Color: Brown, tan, or grey
Luster: Dull to earthy

Identified June 11, 2026More sedimentary →

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Physical properties

Hardness: 6-7 Mohs; Color: Brown, tan, or grey; Luster: Dull to earthy; Texture: Granular and gritty; 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 (clasts). This specific specimen shows river rounding, indicating transport by water in a fluvial environment over centuries.

Uses & applications

Common river stones are used in landscaping, as aggregate in construction, and for decorative masonry. Pure sandstone is used in glass manufacturing and as building stone.

Geological facts

Sandstone accounts for about 10-20% of the sedimentary rocks on Earth. The grit of sandstone is often used for sharpening tools, known as whetstones.

Field identification & locations

Identify by its gritty texture (feels like sandpaper) and visible sand grains. Found globally in riverbeds, canyons, and coastal areas. Collectors often look for examples with unique weathering or fossil inclusions.