sedimentary

Fossiliferous Limestone

Calcium Carbonate (CaCO3) with organic fossil inclusions

Hardness of 3 on the Mohs scale, grayish to tan color, dull to earthy luster, and effervesces strongly when exposed to dilute hydrochloric acid.

Identified November 14, 2026More sedimentary →

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Physical properties

Hardness of 3 on the Mohs scale, grayish to tan color, dull to earthy luster, and effervesces strongly when exposed to dilute hydrochloric acid.

Formed through the accumulation and cementation of skeletal fragments, shells, and coral in shallow marine environments over millions of years.

Used widely in the construction industry as crushed stone, dimension building blocks, and in the production of Portland cement and agricultural lime.

Limestone layers often preserve ancient marine life, providing vital clues about Earth's prehistoric climatic shifts and evolutionary history.

Identify in the field by its pale color, reactive fizz with acid, and visible fossil fragments embedded within the matrix.

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

Sandstone or Siltstone

Arenite (if sandstone)

Fossiliferous Sedimentary Rock

Sedimentary limestone with invertebrate fossil imprint

Shale

Fissile Sedimentary Rock

Sandstone

Arenite

Shale

Clastic sedimentary rock