sedimentary
River Stone (likely Siltstone or fine-grained Quartzite)
Sedimentary clastic rock containing SiO2 and iron oxides
Hardness: 6-7 on Mohs scale; Color: Brownish-tan with dark staining; Luster: Dull to slightly waxy; Structure: Microcrystalline; Cleavage: None; Specific Gravity: 2.6-2.7
- Hardness
- 6-7 on Mohs scale
- Color
- Brownish-tan with dark staining
- Luster
- Dull to slightly waxy
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Brownish-tan with dark staining; Luster: Dull to slightly waxy; Structure: Microcrystalline; Cleavage: None; Specific Gravity: 2.6-2.7
Formation & geological history
Formed through the accumulation and litification of fine-grained sediment (silt/sand) in a water environment, subsequently smoothed and rounded by river erosion over thousands of years.
Uses & applications
Used primarily in landscaping, decorative ground cover, aquarium decor, and sometimes as a substrate in construction drainage systems.
Geological facts
River stones are shaped by 'saltation,' the process of water bouncing rocks against other rocks, which polishes their surfaces naturally over long periods.
Field identification & locations
Identify by its smooth, water-worn rounded edges and lack of visible crystal grains. Found globally in active or ancient riverbeds, beaches, and glacial deposits.
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