sedimentary
River Stone (River Rock)
Smooth Clastic Sedimentary Rock
Mohs hardness of 6-7 (if silica-rich), variable colors of tan, grey, and yellow, dull to waxy luster, smooth well-rounded texture with small pits.
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Physical properties
Mohs hardness of 6-7 (if silica-rich), variable colors of tan, grey, and yellow, dull to waxy luster, smooth well-rounded texture with small pits.
Formation & geological history
Formed through long-term erosion and abrasion in riverbeds or coastal environments. The original parent rock could be igneous or sedimentary, further weathered over thousands of years.
Uses & applications
Commonly used in landscaping, decorative stone masonry, aquarium decor, and as massage stones.
Geological facts
The smooth surface is the result of 'saltation,' where rocks bounce along the bottom of a river, wearing away sharp edges through constant collision.
Field identification & locations
Identified by its rounded, water-worn shape and lack of sharp edges. Can be found in current or ancient riverbeds, beaches, and glacial deposits.
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