sedimentary
River Stone (Sandstone or Siltstone)
Sedimentary Rock (Clastic)
Hardness: 6-7 (Mohs scale), Color: Brownish-tan to earthy grey, Luster: Dull/Earthy, Grain size: Medium to fine, Texture: Gritty, Structure: Massive/Rounded due to abrasion.
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Physical properties
Hardness: 6-7 (Mohs scale), Color: Brownish-tan to earthy grey, Luster: Dull/Earthy, Grain size: Medium to fine, Texture: Gritty, Structure: Massive/Rounded due to abrasion.
Formation & geological history
Formed by the accumulation and lithification of sand-sized mineral particles (usually quartz or feldspar). The rounded shape indicates significant mechanical weathering and transport by water in a river, stream, or beach environment.
Uses & applications
Commonly used in landscaping, construction aggregate, decorative garden features, and sometimes as a base for stone painting or engraving.
Geological facts
River stones are shaped by a process called saltation, where rocks bounce along the bottom of a river bed, slowly wearing away sharp edges until they become smooth and elliptical.
Field identification & locations
Identify by its smooth, rounded surface and gritty texture. Found globally in river valleys and glaciated plains. Collectors often look for unique shapes or colors.
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