sedimentary

River Pebble

Quartzite / Siliciclastic Rock

Hardness of 7 on the Mohs scale, grayish-tan color, dull to vitreous luster, fine-grained crypto-crystalline structure, with no visible cleavage.

Identified October 31, 2026More sedimentary →

Get a report just like this from any photo, free.

Physical properties

Hardness of 7 on the Mohs scale, grayish-tan color, dull to vitreous luster, fine-grained crypto-crystalline structure, with no visible cleavage.

Formed through the continuous water-driven erosion and natural tumbling of parent rocks in riverbeds and stream environments.

Commonly used in landscaping, decorative garden design, walkway gravel, and as a tactile worry stone.

River pebbles develop their smooth, rounded shapes over thousands of years as turbulent water continually grinds them against other rocks.

Easily identified by its exceptionally smooth, rounded surface and dense, resistant feel; found worldwide along active and ancient riverbeds.

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)