Rock Identifier
Fossil-bearing limestone with a likely fossil shell (Bioclastic limestone, chiefly calcite (CaCO₃); fossil identity uncertain from the photo) — fossil
fossil

Fossil-bearing limestone with a likely fossil shell

Bioclastic limestone, chiefly calcite (CaCO₃); fossil identity uncertain from the photo

AI-generated identification · may be incorrect

Tan, fine-grained carbonate rock with a dark, concentric outline around a central fossil-like form. Calcite is Mohs 3, vitreous to dull, and trigonal; rock hardness and density vary with cement and impurities.

Identified More fossil →
Explore Fossil-bearing limestone with a likely fossil shell in the encyclopedia →

Identify your own rocks.

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

App StoreGoogle Play

Physical properties

Tan, fine-grained carbonate rock with a dark, concentric outline around a central fossil-like form. Calcite is Mohs 3, vitreous to dull, and trigonal; rock hardness and density vary with cement and impurities.

Formation & geological history

Shell material or other biological remains accumulated in marine sediment and lithified into limestone. The image alone does not establish the fossil’s identity or geological age.

Uses & applications

Primarily a collecting or teaching specimen; limestone is widely used for cement, aggregate, and building stone.

Geological facts

The dark rings may be fossil boundaries, mineral staining, or markings; a clear identification would require closer examination.

Field identification & locations

Look for repeated shell-like structure and calcite reaction to dilute acid, while noting that acid also reacts with the surrounding limestone. Marine limestones occur worldwide.

More like this

Other fossil specimens

Probable fossil-bearing rock or mineral concretion (Unidentified carbonate-rich concretion with a possible fossil inclusion) — fossil

Probable fossil-bearing rock or mineral concretion

Unidentified carbonate-rich concretion with a possible fossil inclusion

fossil
Likely fossil oyster shell (Fossilized bivalve shell; exact species cannot be identified from the image) — fossil

Likely fossil oyster shell

Fossilized bivalve shell; exact species cannot be identified from the image

fossil
Crinoid Stem Fossil in Matrix (Phylum Echinodermata, Class Crinoidea) — fossil

Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

fossil
Fossiliferous limestone (likely a crinoidal or shell-fragment limestone) (Bioclastic limestone, composed chiefly of calcite (CaCO₃)) — sedimentary

Fossiliferous limestone (likely a crinoidal or shell-fragment limestone)

Bioclastic limestone, composed chiefly of calcite (CaCO₃)

sedimentary
Fossil oyster shell (Oyster (family Ostreidae); shell composed chiefly of calcite (CaCO₃)) — fossil

Fossil oyster shell

Oyster (family Ostreidae); shell composed chiefly of calcite (CaCO₃)

fossil
Weathered fossil bone fragment (identification uncertain) (Fossilized bone; exact taxon and mineral composition cannot be determined from the image) — fossil

Weathered fossil bone fragment (identification uncertain)

Fossilized bone; exact taxon and mineral composition cannot be determined from the image

fossil