sedimentary

Quartz pebble

Silicon dioxide (SiO2)

Hardness of 7 on Mohs scale, yellowish-brown surface staining, vitreous luster, conchoidal fracture, trigonal crystal system.

Identified November 11, 2026More sedimentary →

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Physical properties

Hardness of 7 on Mohs scale, yellowish-brown surface staining, vitreous luster, conchoidal fracture, trigonal crystal system.

Formed through the physical weathering and aqueous transport of older parent rocks, accumulating in fluvial or marine sedimentary environments.

Commonly used in landscaping, aggregate production, and geological study as a durable indicator of transport history.

Quartz is one of the most abundant minerals on Earth's continental crust and extremely resistant to chemical weathering.

Identify in the field by its high hardness, inability to be scratched by a steel knife, and rounded shape from water transport.

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)