metamorphic or sedimentary
River Pebble (Likely Quartzite or Chert)
Silicon Dioxide (SiO2)
Hardness: 7 (Mohs scale), Color: Brownish-tan with weathering, Luster: Dull/Waxy, Crystal Structure: Microcrystalline, Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.7
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Physical properties
Hardness: 7 (Mohs scale), Color: Brownish-tan with weathering, Luster: Dull/Waxy, Crystal Structure: Microcrystalline, Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.7
Formation & geological history
Formed through the metamorphism of sandstone (quartzite) or precipitation of silica (chert). This specific specimen has been smoothed and rounded by long-term fluvial (river) erosion.
Uses & applications
Commonly used in construction aggregate, landscaping, or as a pocket stone. Harder varieties like this were historically used for making stone tools.
Geological facts
River stones take their smooth, rounded shape from thousands of years of tumbling against other rocks in moving water, a process known as saltation.
Field identification & locations
Identify by its rounded 'potato' shape and inability to be scratched by a steel knife. Commonly found in stream beds, glacial deposits, and beaches.
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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