sedimentary
River Rock (Greywacke/Sandstone)
Arenite / Lithic Sandstone
Hardness: 6-7 (Mohs scale), Color: Dull grey to brownish-grey, Luster: Dull/Earthy, Texture: Fine-grained to medium-grained, Shape: Sub-rounded due to water erosion.
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Physical properties
Hardness: 6-7 (Mohs scale), Color: Dull grey to brownish-grey, Luster: Dull/Earthy, Texture: Fine-grained to medium-grained, Shape: Sub-rounded due to water erosion.
Formation & geological history
Formed through the accumulation and cementation of mineral particles or rock fragments. These specific specimens have been smoothed and rounded by long-term transport in riverbeds or coastal environments.
Uses & applications
Commonly used in landscaping, decorative ground cover, construction aggregate, and as 'worry stones' or for rock painting.
Geological facts
River rocks are geological travelers; their rounded shape is a record of the distance they have traveled and the kinetic energy of the water that moved them.
Field identification & locations
Identify by the smooth, rounded exterior and uniform dull color. They are ubiquitous in current and ancient riverbeds, glacial deposits, and beaches.
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