sedimentary

Mixed River Pebbles

Polymictic quartz and silicate pebble aggregate

AI-generated identification · may be incorrect

Hardness varies from 6 to 7 on the Mohs scale due to dominant quartz content. Colors range from earthy brown and tan to grey with vitreous to dull lusters and rounded, weathered crystal structures.

Identified November 3, 2026More sedimentary →

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Physical properties

Hardness varies from 6 to 7 on the Mohs scale due to dominant quartz content. Colors range from earthy brown and tan to grey with vitreous to dull lusters and rounded, weathered crystal structures.

Formation & geological history

Formed through the mechanical weathering, fluvial transport, and rounding of various parent rocks over geological timescales in riverbeds and stream environments.

Uses & applications

Commonly utilized in landscaping, decorative garden pathways, concrete aggregate, and aquarium substrates.

Geological facts

River pebbles undergo natural tumbling and abrasion over thousands of miles of water transport, smoothing away all sharp edges. They serve as natural indicators of ancient river channels and paleohydrology.

Field identification & locations

Easily identified by their smooth, rounded surfaces and lack of sharp cleavage planes, typically found in alluvial deposits, riverbanks, and glacial till worldwide.