sedimentary
River Pebble (Quartzite / Chert)
Silicon Dioxide (SiO2)
Hardness 6.5-7 on Mohs scale; color ranges from yellowish-brown, brown, to dark tan; resinous to earthy or glossy (when wet) luster; smooth, rounded, stream-worn texture with microcrystalline structure.
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Physical properties
Hardness 6.5-7 on Mohs scale; color ranges from yellowish-brown, brown, to dark tan; resinous to earthy or glossy (when wet) luster; smooth, rounded, stream-worn texture with microcrystalline structure.
Formation & geological history
Formed through the mechanical weathering, erosion, and transport of silica-rich rocks in riverbeds, streams, or coastal environments, which smooths and rounds the rock over long periods.
Uses & applications
Used widely in landscaping, decorative rock gardens, aquariums, concrete aggregate, and as general gravel materials.
Geological facts
River pebbles acquire their signature rounded shape from tumbling against other stones and sediments in flowing water, a process known as attrition.
Field identification & locations
Easily identified by its smooth, water-worn, oval or rounded shape and high hardness (scratches glass). Commonly found in current or ancient river beds, gravel pits, and beaches.
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