sedimentary
River Gravel
Polymictic gravel and pebble aggregate
Hardness varies by mineral composition (typically 6-7 on Mohs scale for quartz-rich pebbles); multicolored including browns, tans, greys, and pinks; vitreous to dull luster; amorphous, rounded shape due to water transport.
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Physical properties
Hardness varies by mineral composition (typically 6-7 on Mohs scale for quartz-rich pebbles); multicolored including browns, tans, greys, and pinks; vitreous to dull luster; amorphous, rounded shape due to water transport.
Formation & geological history
Formed through the mechanical weathering, erosion, and long-term aqueous transport of various parent rocks (igneous, metamorphic, and sedimentary) in riverbeds and stream environments.
Uses & applications
Used extensively in construction for concrete aggregate, landscaping, drainage systems, and pathway paving.
Geological facts
River gravel is continuously shaped by hydraulic action, where tumbling against other rocks rounds off sharp edges over thousands to millions of years.
Field identification & locations
Commonly found in active or ancient riverbeds, stream banks, and alluvial deposits worldwide; easily identified by its smooth, rounded surfaces resulting from water tumbling.
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