sedimentary

Fossiliferous Limestone

Calcium Carbonate (CaCO3) with fossil inclusions

Hardness of 3 on the Mohs scale, typically tan to brown in color, dull to earthy luster, and reacts with hydrochloric acid.

Identified October 30, 2026More sedimentary →

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Physical properties

Hardness of 3 on the Mohs scale, typically tan to brown in color, dull to earthy luster, and reacts with hydrochloric acid.

Formed from the accumulation and compaction of marine organism shells and skeletal fragments in shallow marine environments over millions of years.

Used in construction, production of cement, agriculture, and as a decorative stone.

Often contains well-preserved ancient marine fossils like brachiopods, crinoids, and bryozoans visible on weathered surfaces.

Easily identified by its reaction to acid and visible fossil fragments; found globally in regions with ancient marine sedimentary basins.

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)