sedimentary

Crushed Limestone

Calcium Carbonate (CaCO3)

Mohs hardness of 3, colors range from white to gray and tan, dull to earthy luster, fine-grained texture.

Identified November 3, 2026More sedimentary →

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Physical properties

Mohs hardness of 3, colors range from white to gray and tan, dull to earthy luster, fine-grained texture.

Formed from the accumulation of skeletal fragments of marine organisms in shallow tropical marine environments over millions of years.

Extensively used in construction as aggregate for concrete, road base, and in the production of cement and agricultural lime.

Limestone dissolves slightly in acidic water, frequently creating extensive underground cave systems and sinkholes.

Easily identified by its characteristic fizz when a drop of dilute hydrochloric acid is applied due to carbon dioxide release.

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)