Mixed (Sedimentary, Igneous, and Metamorphic)
River Rocks (Polished River Pebbles)
Stream-rounded clastic sediments
Hardness: Variable (mostly 6-7 on Mohs scale), Color: Multicolored (tans, greys, blacks, greens), Luster: Dull to waxy when wet, Crystal structure: Varies by rock type, Specific gravity: 2.5-2.8
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Physical properties
Hardness: Variable (mostly 6-7 on Mohs scale), Color: Multicolored (tans, greys, blacks, greens), Luster: Dull to waxy when wet, Crystal structure: Varies by rock type, Specific gravity: 2.5-2.8
Formation & geological history
Formed through mechanical erosion and abrasion in high-energy fluvial (river) environments over thousands of years; these specimens represent a mix of geological ages from various parent formations.
Uses & applications
Landscaping, decorative garden mulch, aquarium substrate, construction aggregate, and occasionally used in mosaics or as base materials for paths.
Geological facts
The smooth, rounded shape is the result of 'saltation'—the process where rocks bounce along riverbeds, grinding against each other until sharp edges are worn away. The green specimen is likely serpentinite or greenstone.
Field identification & locations
Identify in the field by their smooth, rounded edges and lack of sharp fractures; commonly found in riverbeds, glacial till, and coastal beaches. Collectors look for unique patterns or rare minerals within the mix.
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