sedimentary

Sandstone (Quartzite-rich River Cobble)

Clastic sedimentary rock (primarily SiO2)

AI-generated identification · may be incorrect

Hardness: 6-7 Mohs; Color: Tan, beige, or light brown; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; Cleavage: None; Specific gravity: 2.3–2.4

Hardness: 6-7 Mohs
Color: Tan, beige, or light brown
Luster: Dull/Earthy

Identified April 12, 2026More sedimentary →

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Physical properties

Hardness: 6-7 Mohs; Color: Tan, beige, or light brown; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; Cleavage: None; Specific gravity: 2.3–2.4

Formation & geological history

Formed from the accumulation and cementation of mineral particles (sand); this specific specimen has been rounded and polished through fluvial processes (water erosion in a river or stream) over thousands to millions of years.

Uses & applications

Used primarily as decorative landscaping stone, in construction aggregates, and occasionally as a primitive tool (grinding stone/hand axe) by early humans.

Geological facts

Sandstone contains about 20-25% of the world's groundwater. The rounded shape indicates a long journey through a body of water, smoothing away all sharp edges of the original parent rock.

Field identification & locations

Identify in the field by its gritty texture (feels like sandpaper) and rounded, water-worn exterior. Found globally in riverbeds, glacial deposits, and beaches.