sedimentary

Fossiliferous limestone

Bioclastic limestone, primarily calcite (CaCO₃)

AI-generated identification · may be incorrect

Gray-beige, granular and dull to lightly sparkling, with visible shell or fossil fragments; Mohs hardness 3, nonmetallic luster, calcite crystals, and weak to moderate rhombohedral cleavage. It should effervesce strongly with dilute hydrochloric acid or vinegar.

Identified September 17, 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

A sedimentary rock formed from accumulated marine shells, skeletal debris, and carbonate mud that lithified and recrystallized, commonly during Paleozoic–Mesozoic marine episodes. The visible curved fragments appear bioclastic, though the image alone cannot determine the exact fossil or age.

Uses & applications

Used as crushed aggregate, cement and lime feedstock, building stone, and occasionally as a fossil-collecting specimen; generally unsuitable for fine jewelry.

Geological facts

The porous, shell-rich texture records ancient shallow seas and reef or seafloor environments. Some specimens may contain crinoid, brachiopod, or mollusk fragments.

Field identification & locations

Identify by its abundant fossil debris, relatively soft surface, and acid reaction; common in marine sedimentary basins worldwide. A hand lens and acid test are useful for confirmation.