igneous
River Pebbles (including Granite and Basalt)
Mixed Igneous Rocks (Granite, Basalt)
Hardness: 6-7 on Mohs scale. Colors: Grey, pink, reddish-brown, dark green/black. Luster: Dull to sub-vitreous. Texture: Smooth, rounded from water abrasion.
- Hardness
- 6-7 on Mohs scale
- Luster
- Dull to sub-vitreous
Identified More igneous →
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Physical properties
Hardness: 6-7 on Mohs scale. Colors: Grey, pink, reddish-brown, dark green/black. Luster: Dull to sub-vitreous. Texture: Smooth, rounded from water abrasion.
Formation & geological history
Formed via cooling of magma or lava (igneous processes), later eroded, weathered, and rounded by stream or wave action over thousands to millions of years.
Uses & applications
Used in landscaping, aquarium decor, gravel paths, drainage systems, and as decorative stone.
Geological facts
Water abrasion naturally smooths rocks over long distances, transforming jagged mountain fragments into rounded pebbles.
Field identification & locations
Identify by their smooth, rounded sub-spherical shape and varied mineral compositions (e.g. pink potassium feldspar in granite). Extremely common along riverbeds, lakeshores, and glacial deposits.
