sedimentary

Limestone

Calcium Carbonate (CaCO3)

Mohs hardness of 3, colors range from white to gray and brown, dull to earthy luster, fine-grained crystal structure.

Identified November 6, 2026More sedimentary →

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Physical properties

Mohs hardness of 3, colors range from white to gray and brown, dull to earthy luster, fine-grained crystal structure.

Formed through the accumulation of skeletal fragments of marine organisms or chemical precipitation in shallow marine environments.

Extensively used in construction as building stone, aggregate in concrete, and manufacturing lime and cement.

Limestone frequently contains well-preserved fossils and forms dramatic landscapes like caves and karst topography.

Easily identified by its characteristic effervescence when exposed to dilute hydrochloric acid.

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)