sedimentary
Pebble
Lithified rock fragment / Sedimentary clast
Hardness varies based on composition (typically Mohs 6-7 if quartz-rich), colors range from grey to brown, dull luster, amorphous or cryptocrystalline structure depending on the parent rock type.
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Physical properties
Hardness varies based on composition (typically Mohs 6-7 if quartz-rich), colors range from grey to brown, dull luster, amorphous or cryptocrystalline structure depending on the parent rock type.
Formation & geological history
Formed through weathering, erosion, and transport of larger rock masses by water or wind, smoothing their edges over time in riverbeds or beaches.
Uses & applications
Used in landscaping, decorative ground cover, and construction aggregate.
Geological facts
Pebbles are officially classified by their grain size in the Wentworth scale, ranging from 4 to 64 millimeters in diameter.
Field identification & locations
Commonly found in stream beds, gravel bars, and ancient sedimentary deposits. Useful for studying local geology and erosion patterns.
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Sandstone or Siltstone
Arenite (if sandstone)
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Fossiliferous Concretion
Septarian Concretion containing Brachiopods/Crinoids
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Quartz pebble
Silicon dioxide (SiO2)
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Generic Pebble / Rock Fragment
Lithic fragment / Weathered rock
sedimentary
Banded Siltstone / Mudstone Pebble
Siltstone / Argillite
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Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary