Rock Identifier
Pebble (Lithified rock fragment / Sedimentary clast) — sedimentary
sedimentary

Pebble

Lithified rock fragment / Sedimentary clast

AI-generated identification · may be incorrect

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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Other sedimentary specimens

Fossil-bearing concretion, possibly containing a fossil shell or other organic inclusion (Calcareous concretion; exact fossil and host-rock composition are not identifiable from the image) — fossil

Fossil-bearing concretion, possibly containing a fossil shell or other organic inclusion

Calcareous concretion; exact fossil and host-rock composition are not identifiable from the image

fossil
Fossiliferous Sedimentary Rock (Sedimentary limestone with invertebrate fossil imprint) — fossil

Fossiliferous Sedimentary Rock

Sedimentary limestone with invertebrate fossil imprint

fossil
Sandstone or Siltstone (Arenite (if sandstone)) — Sedimentary

Sandstone or Siltstone

Arenite (if sandstone)

Sedimentary
Sandstone (Arenite) — sedimentary

Sandstone

Arenite

sedimentary
Shale (Shale (clastic sedimentary rock)) — sedimentary

Shale

Shale (clastic sedimentary rock)

sedimentary
Shale (or Mudstone/Siltstone) (Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)) — sedimentary

Shale (or Mudstone/Siltstone)

Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)

sedimentary