sedimentary

Sandstone

Arenite

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

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

Identified June 20, 2026More sedimentary →

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Physical properties

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

Formation & geological history

Formed through the accumulation and cementation of mineral particles or rock fragments (sand) over millions of years. This specimen appears to be of the 'Greywacke' or 'Lithic Arenite' sub-type common in various geological eras.

Uses & applications

Widely used in construction for paving and building; historically used for millstones and sharpening stones; can be a reservoir for oil and natural gas.

Geological facts

Sandstone makes up about 10-20% of the Earth's total sedimentary rock. It is porous and often acts as a natural filter for groundwater.

Field identification & locations

Identify by its gritty 'sandpaper' feel. It is commonly found in river beds, beaches, and desert dunes. This specific piece looks like common landscape gravel.