sedimentary

Quartz Pebble

Silicon dioxide (SiO2)

Hardness of 7 on the Mohs scale, white to translucent color, vitreous luster, conchoidal fracture, specific gravity of 2.65.

Identified November 14, 2026More sedimentary →

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Physical properties

Hardness of 7 on the Mohs scale, white to translucent color, vitreous luster, conchoidal fracture, specific gravity of 2.65.

Formed from the weathering and water-transport of larger quartz-bearing rocks, smoothed over long periods in fluvial or marine environments.

Used in landscaping, aggregate, abrasive manufacturing, and as a common tumbling stone for rockhounds.

Quartz is one of the most abundant and durable minerals in Earth's continental crust, highly resistant to both chemical and physical weathering.

Identified by its high hardness (scratches glass) and lack of cleavage; commonly found in riverbeds, beaches, and conglomerate rock formations.

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

Sandstone or Siltstone

Arenite (if sandstone)

Fossiliferous Sedimentary Rock

Sedimentary limestone with invertebrate fossil imprint

Shale

Fissile Sedimentary Rock

Sandstone

Arenite

Shale

Clastic sedimentary rock