sedimentary
Brown Pebble (Probable Chert or Siltstone)
Silicon Dioxide (SiO2) / Sedimentary Microcrystalline Quartz
Hardness: 6.5-7 (Mohs scale), Color: Brown/Earth tones, Luster: Dull to Waxy, Structure: Cryptocrystalline/Massive, Cleavage: None (Conchoidal fracture)
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Brown/Earth tones, Luster: Dull to Waxy, Structure: Cryptocrystalline/Massive, Cleavage: None (Conchoidal fracture)
Formation & geological history
Formed by the precipitation of silica from groundwater or the accumulation of silica-rich organic remains in sedimentary layers. Often rounded by fluvial or coastal transport over thousands of years.
Uses & applications
Common river stones used for landscaping, aggregate in construction, or primitive tool making (flintknapping).
Geological facts
Small brown pebbles like this are among the most common rocks found globally in riverbeds. Their rounded shape is a result of mechanical weathering through water transport.
Field identification & locations
Identify by its hardness (will scratch glass) and smooth, water-worn texture. Commonly found in gravel pits, riverbanks, and beaches worldwide.
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