sedimentary
River Rock
Silica-rich water-worn rock / Quartzite
Hardness: 7 on Mohs scale (if quartzite); Color: brownish-gray; Luster: dull to vitreous; Structure: massive, rounded by water abrasion; Cleavage: none due to tumbling.
- Hardness
- 7 on Mohs scale (if quartzite)
- Color
- brownish-gray
- Luster
- dull to vitreous
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Physical properties
Hardness: 7 on Mohs scale (if quartzite); Color: brownish-gray; Luster: dull to vitreous; Structure: massive, rounded by water abrasion; Cleavage: none due to tumbling.
Formation & geological history
Formed through prolonged water transport and mechanical weathering in riverbeds and streams, smoothing angular rock fragments over thousands to millions of years.
Uses & applications
Landscaping, garden decoration, aquarium substrates, construction aggregate, and pathway paving.
Geological facts
Water-worn stones have been used by humans since prehistoric times for tools, cooking stones, and ornamentation due to their smooth, comfortable shapes.
Field identification & locations
Found abundantly in and along riverbeds, streams, and ancient glacial deposits worldwide. Easily identified by its smooth, rounded edges and water-worn exterior.
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