sedimentary

Fossiliferous Limestone

Autochthonous Biogenic Sedimentary Rock (CaCO3)

Hardness: 3 (Mohs scale); Color: Cream, tan, or grey; Luster: Dull/Earthy; Structure: Clastic or crystalline matrix containing visible brachiopod or bivalve imprints; Cleavage: None (conchoidal to uneven fracture).

Hardness: 3 (Mohs scale)
Color: Cream, tan, or grey
Luster: Dull/Earthy

Identified June 21, 2026More sedimentary →

Explore Fossiliferous Limestone in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Formed in shallow marine environments from the accumulation of calcium carbonate shells and skeletal fragments. Most specimens date from the Paleozoic or Mesozoic eras.

Uses & applications

Used in the production of cement, as a building stone (dimension stone), in agriculture to neutralize soil acidity, and as common collector specimens for amateur paleontologists.

Geological facts

This specimen contains clear impressions of prehistoric marine life, likely brachiopods. Limestone makes up about 10% of the total volume of all sedimentary rocks on Earth.

Field identification & locations

Identify in the field by searching for visible shell fragments or imprints; it will effervesce (fizz) strongly when exposed to dilute hydrochloric acid or vinegar. Common in regions with ancient seabed outcrops.

Other sedimentary specimens

See all

Sandstone or Siltstone

Arenite (if sandstone)

Sedimentary

Cone-in-cone structure (Limestone)

Cone-in-cone structure (Secondary Sedimentary Structure)

sedimentary

Chert Breccia

Brecciated Chert (Microcrystalline Silica)

sedimentary

Sandstone Grain

Clastic Sedimentary Rock Grain (SiO2 dominated)

sedimentary

Shale or Slaty Mudstone

Argillaceous sedimentary rock

sedimentary

Sandstone

Arenite (primarily SiO2)

sedimentary