sedimentary
River Pebble (likely Quartzite or Siltstone)
Sedimentary Clast (SiO2 based)
Hardness: 6-7 (Mohs); Color: Tan, brown, and grey with iron staining; Luster: Dull/Earthy; Structure: Clastic/Granular; Cleavage: None.
- Hardness
- 6-7 (Mohs)
- Color
- Tan, brown, and grey with iron staining
- Luster
- Dull/Earthy
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Physical properties
Hardness: 6-7 (Mohs); Color: Tan, brown, and grey with iron staining; Luster: Dull/Earthy; Structure: Clastic/Granular; Cleavage: None.
Formation & geological history
Formed through the erosion and weathering of larger rock formations, subsequently transported and rounded by water action in a river or stream environment. Its age can range from thousands to millions of years depending on the parent rock source.
Uses & applications
Primarily used in landscaping, construction aggregate, aquarium decor, and as a tactile object for hobbyist collectors.
Geological facts
The smooth, rounded shape is a result of 'attritional wear,' where rocks collide with each other in moving water, wearing down sharp edges over time. Small pebbles like this are key indicators of past water flow in geological surveys.
Field identification & locations
Identify by its smooth, water-worn texture and rounded edges. Common in riverbeds, glacial deposits, and beaches. Collectors often use them for rock tumbling or as base materials for painted rock art.
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