sedimentary
River Gravel (Quartzite and Chert pebbles)
Silicon Dioxide (SiO2)
Hardness: 6.5-7 on Mohs scale. Color: Tan, brown, gray, and cream. Luster: Dull to waxy. Structure: Microcrystalline or granular. Cleavage: None, conchoidal fracture.
- Hardness
- 6
- Color
- Tan, brown, gray, and cream
- Luster
- Dull to waxy
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Physical properties
Hardness: 6.5-7 on Mohs scale. Color: Tan, brown, gray, and cream. Luster: Dull to waxy. Structure: Microcrystalline or granular. Cleavage: None, conchoidal fracture.
Formation & geological history
Formed through the weathering and erosion of larger rock formations, transported by water and naturally tumbled into smooth pebbles over thousands of years.
Uses & applications
Commonly used in landscaping, concrete aggregate, road construction, and decorative garden paths.
Geological facts
These pebbles are silica-rich, making them extremely resistant to chemical weathering. They often survive long journeys from mountains to river basins.
Field identification & locations
Identify by their rounded shape and inability to be scratched by a steel knife. Commonly found in riverbeds, glacial deposits, and beaches.
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