sedimentary

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness of 7 on the Mohs scale, vitreous luster, conchoidal fracture, and white to gray color with brownish weathering.

Identified October 23, 2026More sedimentary →

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Physical properties

Hardness of 7 on the Mohs scale, vitreous luster, conchoidal fracture, and white to gray color with brownish weathering.

Formed through intense weathering and aqueous transport of quartz veins or silicious rocks, smoothed by water action in river or beach environments.

Used in landscaping, decorative aggregates, and occasionally tumbled for lapidary crafts.

Quartz is one of the most abundant and stable minerals on Earth's surface, resisting chemical weathering over millions of years.

Identified by its high hardness (scratches glass), lack of cleavage, and smooth water-worn shape found abundantly in riverbeds and gravel bars.

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)