metamorphic or sedimentary
River Pebble (likely Quartzite or Chert)
Silicon Dioxide (SiO2)
Hardness: Approx. 7 (Mohs scale), Color: Tan, brown, or buff with mottling, Luster: Dull or sub-waxy (waxy when wet), Crystal structure: Microcrystalline or non-clastic, Cleavage: None/Conchoidal fracture.
- Hardness
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Physical properties
Hardness: Approx. 7 (Mohs scale), Color: Tan, brown, or buff with mottling, Luster: Dull or sub-waxy (waxy when wet), Crystal structure: Microcrystalline or non-clastic, Cleavage: None/Conchoidal fracture.
Formation & geological history
Formed through the erosion and transport of larger rock masses (such as sandstone or metamorphic quartzite) by water. The rounded shape indicates significant travel in a river or stream bed where abrasive forces smoothed the edges.
Uses & applications
Commonly used in landscaping, decorative ground cover, aquarium gravel, and construction aggregate. If high in quartz, it can be used for tumbling by hobbyists.
Geological facts
River pebbles are smoothed by the natural process of 'attrition,' where rocks collide with one another in moving water, effectively sandblasting themselves over years or decades.
Field identification & locations
Identify by its rounded, smooth 'water-worn' texture and lack of sharp edges. These are ubiquitous in riverbeds, glacial deposits, and coastal areas.
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Other metamorphic or sedimentary specimens
Quartz
Quartz (SiO2 - Silicon Dioxide)
Mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Milky Quartz
Quartz (Silicon Dioxide - SiO2)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Pebble (likely Quartz or Chert)
SiO₂ (Silicon Dioxide) - referring to the likely main mineral composition, Quartz. If it's chert, the scientific name remains SiO₂ with a microcrystalline structure.
Sedimentary Rock