sedimentary

River Pebble (Sandstone)

Clastic Sedimentary Rock (Sandstone)

AI-generated identification · may be incorrect

Hardness: 6-7 Mohs; Color: Tan, beige, and grey; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; Cleavage: None; Specific gravity: 2.2-2.8

Hardness: 6-7 Mohs
Color: Tan, beige, and grey
Luster: Dull/Earthy

Identified June 21, 2026More sedimentary →

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Physical properties

Hardness: 6-7 Mohs; Color: Tan, beige, and grey; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; 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. This specimen shows significant rounding due to water erosion (fluvial transport) over hundreds to thousands of years.

Uses & applications

Primarily used in landscaping, construction as aggregate, and sometimes in decorative masonry. Smoothed river stones are often used for decorative garden paths or in fish tanks.

Geological facts

The rounded shape indicates that this rock has traveled a long distance in a river or creek bed, where constant tumbling against other rocks has smoothed away its sharp edges.

Field identification & locations

Identify in the field by its rounded, smooth texture and sandy granular appearance under a magnifying glass. Commonly found in riverbeds, old glacial deposits, and along coastal beaches.