sedimentary

River Pebbles (Mixed Lithology)

Conglomerate clasts (Silica-rich and Metamorphic assemblages)

AI-generated identification · may be incorrect

Hardness: 6-7 (Mohs); Color: Grey, white, green, and banded; Luster: Dull to waxy; Texture: Smooth, water-worn, rounded; Specific Gravity: ~2.6-2.8

Hardness: 6-7 (Mohs)
Color: Grey, white, green, and banded
Luster: Dull to waxy

Identified June 10, 2026More sedimentary →

Explore River Pebbles (Mixed Lithology) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 6-7 (Mohs); Color: Grey, white, green, and banded; Luster: Dull to waxy; Texture: Smooth, water-worn, rounded; Specific Gravity: ~2.6-2.8

Formation & geological history

Formed through the mechanical weathering and transport of various parent rocks (magmatic and metamorphic) in high-energy fluvial environments like rivers or beaches. These specimens are likely Holocene to Pleistocene in transport age.

Uses & applications

Decorative landscaping, aquarium substrate, construction aggregate, and amateur rock collecting (lapidary tumbling).

Geological facts

The smooth, rounded shape is a result of 'attrition,' where rocks collide with each other in water currents, gradually wearing down sharp edges over hundreds of miles of travel.

Field identification & locations

Identify by their rounded, smooth texture and lack of sharp edges. They are found in riverbeds, glacial till, and coastal shorelines globally. These specific pieces show quartz and possible schist/gneiss origins.