sedimentary

Mixed river pebbles (gravel)

Polymictic alluvial gravel; diverse clasts, likely including quartz, feldspar-rich granitoids, and metamorphic rocks

AI-generated identification · may be incorrect

Rounded, water-worn pebbles of varied colors and textures; mineral hardness and luster vary by clast, with quartz-rich pieces typically Mohs 7. Individual grains show no single crystal structure or cleavage pattern.

Identified October 1, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed as assorted bedrock fragments were weathered, transported, and rounded by flowing water, then deposited in river channels or gravel bars. Their ages vary with source rocks and cannot be determined from the image.

Uses & applications

Used for landscaping, drainage, pathways, concrete aggregate, and decorative applications; individual attractive pebbles may be collected.

Geological facts

The rounded shapes indicate sustained abrasion during transport; the assortment suggests multiple source rocks rather than one uniform lithology.

Field identification & locations

Identify by smooth, rounded surfaces and mixed lithologies; compare individual stones’ grain size, banding, and hardness. Common in riverbeds, alluvial deposits, and commercially sold landscaping gravel.