sedimentary

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness of 7 on Mohs scale, white to yellowish-brown color, vitreous luster, conchoidal fracture, trigonal crystal system.

Identified November 8, 2026More sedimentary →

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Physical properties

Hardness of 7 on Mohs scale, white to yellowish-brown color, vitreous luster, conchoidal fracture, trigonal crystal system.

Formed through the mechanical weathering and water transportation of parent quartz veins or pegmatites, often deposited in riverbeds or beaches.

Used in landscaping, abrasive manufacturing, glass production, and as a common specimen for rock tumblers and hobbyists.

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

Easily identified by its high hardness (scratches glass) and lack of cleavage; found globally in gravel deposits and sedimentary 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

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)