sedimentary
Limestone Concretion
Calcium Carbonate Concretion (CaCO3)
AI-generated identification · may be incorrectHardness of 3 on the Mohs scale, earthy brown to gray color, dull luster, microcrystalline structure, and uneven fracture.
Identified More sedimentary →
Explore Limestone Concretion in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 3 on the Mohs scale, earthy brown to gray color, dull luster, microcrystalline structure, and uneven fracture.
Formation & geological history
Formed through the precipitation of mineral cement within the spaces between sediment grains, typically during burial diagenesis.
Uses & applications
Primarily used as geological specimen collectables, educational tools, and occasionally in landscaping or ornamental rock gardens.
Geological facts
Concretions often form around a central nucleus, such as a fossil shell or organic fragment, and weather out of softer surrounding shales or limestones.
Field identification & locations
Identify by its distinct rounded or nodular shape and positive effervescence when tested with dilute hydrochloric acid. Commonly found in sedimentary strata worldwide.
More like this
Other sedimentary specimens
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
fossil
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary