sedimentary
River Pebble
Siliceous rock fragment
Hardness varies from 6 to 7 on the Mohs scale depending on mineral content; usually quartz-rich. Color ranges from gray, brown, to tan. Luster is dull to vitreous. Cryptocrystalline or fine-grained structure, with a smooth, rounded shape due to water erosion.
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Physical properties
Hardness varies from 6 to 7 on the Mohs scale depending on mineral content; usually quartz-rich. Color ranges from gray, brown, to tan. Luster is dull to vitreous. Cryptocrystalline or fine-grained structure, with a smooth, rounded shape due to water erosion.
Formation & geological history
Formed through the mechanical weathering, transport, and erosion of parent rocks (such as granite, quartzite, or sandstone) along riverbeds and streams over thousands to millions of years.
Uses & applications
Used in landscaping, decorative garden paths, construction aggregate, and as skipping stones or canvases for painted art rocks.
Geological facts
Water-worn pebbles like this develop their characteristic smooth surfaces through the process of abrasion, where rocks bump against each other and the riverbed as current carries them downstream.
Field identification & locations
Commonly found in and along riverbeds, beaches, and glacial outwash plains worldwide. Identify by its smooth, water-worn exterior and rounded shape.
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