sedimentary

Fossiliferous Limestone

Biogenic Sedimentary Rock (Calcite, CaCO3)

Hardness of 3 on the Mohs scale, typically off-white to grey or tan, dull to earthy luster, with visible fossil fragments.

Identified November 7, 2026More sedimentary →

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

Physical properties

Hardness of 3 on the Mohs scale, typically off-white to grey or tan, dull to earthy luster, with visible fossil fragments.

Formed by the accumulation and compaction of organic carbonate debris and shells in shallow marine environments over millions of years.

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

Limestone often preserves ancient marine ecosystems, and many architectural monuments worldwide are built from it.

Identified easily by its light color and effervescence when exposed to hydrochloric acid; found globally in 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)