sedimentary

River Pebble

Siliceous rock fragment / Quartzite / Sandstone pebble

AI-generated identification · may be incorrect

Hardness: 6-7 on Mohs scale; Color: Brownish-gray, weathered; Luster: Dull to vitreous; Structure: Microcrystalline to clastic; Cleavage: None (fractures conchoidally); Specific gravity: 2.6-2.7

Hardness: 6-7 on Mohs scale
Color: Brownish-gray, weathered
Luster: Dull to vitreous

Identified August 4, 2026More sedimentary →

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Physical properties

Hardness: 6-7 on Mohs scale; Color: Brownish-gray, weathered; Luster: Dull to vitreous; Structure: Microcrystalline to clastic; Cleavage: None (fractures conchoidally); Specific gravity: 2.6-2.7

Formation & geological history

Formed through the mechanical weathering, erosion, and transport of parent rock materials (often quartz-rich sandstone or quartzite) along riverbeds and streams over thousands to millions of years.

Uses & applications

Used in landscaping, decorative garden stones, construction aggregate, and as a natural smoothing stone in various crafts.

Geological facts

The smooth, rounded shape of a river pebble is caused by water tumbling the rock over long distances, causing it to collide with other rocks and sand in a process called attrition.

Field identification & locations

Identified by its smooth, water-worn, rounded shape and lack of sharp edges. Commonly found in riverbeds, lake shores, and ancient alluvial deposits worldwide.