sedimentary

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness of 7 on the Mohs scale, typically yellow-brown or tan due to iron staining, vitreous to dull luster, and conchoidal fracture.

Identified October 26, 2026More sedimentary →

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Physical properties

Hardness of 7 on the Mohs scale, typically yellow-brown or tan due to iron staining, vitreous to dull luster, and conchoidal fracture.

Formed through the mechanical weathering and prolonged aqueous transportation of parent quartz rocks in high-energy sedimentary environments.

Used in landscaping, decorative stone, abrasive manufacturing, and as tumbled specimens for rock collectors.

Quartz is one of the most abundant and durable minerals in Earth's continental crust, surviving weathering processes that destroy other minerals.

Easily identified by its high hardness, rounded shape from water tumbling, and lack of cleavage. Commonly found in stream beds and beaches.

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

Fossiliferous Sedimentary Rock

Sedimentary limestone with invertebrate fossil imprint

Sandstone or Siltstone

Arenite (if sandstone)

Sandstone

Arenite

Shale

Shale (clastic sedimentary rock)

Shale (or Mudstone/Siltstone)

Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)