sedimentary

Limestone

Calcium Carbonate (CaCO3)

Hardness of 3 on Mohs scale, typically white, gray, or tan in color, with a dull to earthy luster and poor crystal cleavage.

Identified November 8, 2026More sedimentary →

Get a report just like this from any photo, free.

Physical properties

Hardness of 3 on Mohs scale, typically white, gray, or tan in color, with a dull to earthy luster and poor crystal cleavage.

Formed from the accumulation of skeletal fragments of marine organisms like coral, molluscs, and foraminifera over millions of years.

Widely used in construction as a building material, in the production of cement, and as an agricultural soil conditioner.

Limestone formations often host extensive cave systems and well-preserved fossils due to the calm marine environments where they originate.

Easily identified by its reaction to dilute hydrochloric acid, which causes it to fizz and release carbon dioxide gas.

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)