sedimentary
River Pebble
Weathered Rock Fragment
Hardness varies based on mineral composition (typically 6-7 on Mohs scale if quartz-based); gray to brown color; dull luster; amorphous or cryptocrystalline structure; no distinct cleavage; specific gravity around 2.65.
Identified More sedimentary →
Explore River Pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness varies based on mineral composition (typically 6-7 on Mohs scale if quartz-based); gray to brown color; dull luster; amorphous or cryptocrystalline structure; no distinct cleavage; specific gravity around 2.65.
Formation & geological history
Formed through the weathering and erosion of parent rocks, followed by transport via rivers and streams where water action rounds the edges over long periods.
Uses & applications
Used in landscaping, decorative garden paths, concrete aggregate, and sometimes in hobbyist rock tumbling.
Geological facts
Water-worn pebbles can travel miles downstream from their original source, becoming progressively smoother and more rounded due to abrasion against other rocks in the riverbed.
Field identification & locations
Commonly found along riverbeds, beaches, and ancient alluvial deposits. Identified by its smooth, rounded shape and lack of sharp edges.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Fossiliferous Concretion
Septarian Concretion containing Brachiopods/Crinoids
fossil
Generic Pebble / Rock Fragment
Lithic fragment / Weathered rock
sedimentary
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Banded Siltstone / Mudstone Pebble
Siltstone / Argillite
sedimentary