sedimentary

Quartz pebble with dark inclusion

Silicon dioxide (SiO2) with host rock matrix

Hardness of 7 on the Mohs scale, white and dark brown coloration, vitreous luster, conchoidal fracture, specific gravity of 2.65.

Identified October 21, 2026More sedimentary →

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Physical properties

Hardness of 7 on the Mohs scale, white and dark brown coloration, vitreous luster, conchoidal fracture, specific gravity of 2.65.

Formed through the mechanical weathering and water transport of larger quartz-bearing rocks, smoothing into a pebble over millions of years.

Used in landscaping, decorative stone, erosion control, and as a raw material in aggregate production.

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

Identify in the field by its high hardness which easily scratches glass and its smooth, water-worn shape found in riverbeds 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)