sedimentary
Sandstone Pebble (River Cobble)
Arenite (Sandstone)
Hardness: 6-7 on Mohs scale; Color: Greyish-brown to tan; Luster: Dull/earthy; Texture: Fine-grained, gritty to the touch, well-rounded by stream action
- Hardness
- 6-7 on Mohs scale
- Color
- Greyish-brown to tan
- Luster
- Dull/earthy
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Greyish-brown to tan; Luster: Dull/earthy; Texture: Fine-grained, gritty to the touch, well-rounded by stream action
Formation & geological history
Formed by the accumulation and cementation of sand-sized mineral particles (mostly quartz and feldspar) in fluvial or marine environments. This specific piece has undergone mechanical weathering and stream transport, smoothing its edges.
Uses & applications
Used in construction, landcaping, decorative gardens, aquariums, and road sub-base material. Common as everyday pebbles or stones.
Geological facts
Stream-rounded rocks like this are often referred to as river stones or cobbles. Over thousands of years, water currents tumble these rocks against each other, grinding away sharp edges.
Field identification & locations
Identified by its sandy, gritty texture, uniform brownish-grey color, and smooth rounded shape resulting from stream erosion. Commonly found in riverbeds, beaches, and glacial till worldwide.
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