sedimentary

Sandstone (River Stone)

Arenite (primarily SiO2)

AI-generated identification · may be incorrect

Hardness: 6-7 Mohs; Color: Tan, brown, or buff; Luster: Dull/Earthy; Crystal structure: Clastic (sand-sized grains); Cleavage: None; Specific gravity: 2.2-2.8

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

Identified June 13, 2026More sedimentary →

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Physical properties

Hardness: 6-7 Mohs; Color: Tan, brown, or buff; Luster: Dull/Earthy; Crystal structure: Clastic (sand-sized grains); Cleavage: None; Specific gravity: 2.2-2.8

Formation & geological history

Formed through the accumulation and cementation of sand-sized mineral particles or rock fragments, typically in riverbeds, deltas, or deserts. This specific specimen has been rounded by fluvial (river) erosion over thousands of years.

Uses & applications

Used primarily as decorative landscaping stone, in construction aggregates, and occasionally as a sharpening stone or for architectural veneers.

Geological facts

Sandstone accounts for about 10 to 20 percent of all sedimentary rocks on Earth. This rounded 'cobble' shape indicates it spent a significant amount of time being tumbled in a high-energy water environment like a river or beach.

Field identification & locations

Identify by its gritty, sandpaper-like texture and visible sand grains. Common in river basins and sedimentary outcrops worldwide. Collectors look for unique banding or fossil inclusions.