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 grey; Luster: Dull/Earthy; Structure: Granular/Clastic; Cleavage: None; Specific Gravity: 2.2-2.8

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

Identified April 4, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs); Color: Tan, beige, or light grey; Luster: Dull/Earthy; Structure: Granular/Clastic; Cleavage: None; Specific Gravity: 2.2-2.8

Formation & geological history

Formed from the accumulation and cementation of mineral particles (sand). This specific specimen shows significant rounding, indicating it was eroded and transported by water (river or beach action) over a long period.

Uses & applications

Commonly used in construction as an aggregate, for landscaping, and historically as building stone or grindstones.

Geological facts

Sandstone makes up about 20-25% of all sedimentary rocks. Because it is porous, it often serves as a primary reservoir for ground water and petroleum.

Field identification & locations

Identify by its 'sandpaper' feel and visible tiny grains. It is extremely common worldwide in dry environments and along riverbeds. For collectors, it is a basic educational specimen.