sedimentary

Sandstone Concretion

Sedimentary Concretion (Quartz arenite)

Hardness of 6-7 on the Mohs scale due to quartz content. Color ranges from tan to reddish-brown with a dull luster and massive crystal structure.

Identified October 18, 2026More sedimentary →

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Physical properties

Hardness of 6-7 on the Mohs scale due to quartz content. Color ranges from tan to reddish-brown with a dull luster and massive crystal structure.

Formed through the precipitation of mineral cement within the pores of sedimentary strata, often around a nucleus, over millions of years.

Primarily collected as a geological curiosity or used locally as an ornamental landscaping stone.

Concretions are frequently mistaken for fossils or cannonballs due to their remarkably spherical or disc-like shapes.

Found weathering out of sedimentary rock layers globally. Easily identified by its distinct rounded morphology and gritty sandstone texture.

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)