sedimentary

Fossiliferous limestone

Bioclastic limestone, composed mainly of calcite (CaCO₃)

AI-generated identification · may be incorrect

Typically gray, cream, or tan with visible shell or fossil fragments; calcite has Mohs hardness 3, vitreous to dull luster, rhombohedral cleavage, and fizzes with dilute hydrochloric acid. The specimen appears weathered and possibly polished or naturally smoothed.

Identified August 8, 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

Forms when marine shells and skeletal debris accumulate, compact, and cement on ancient seafloors; age may range from Paleozoic to Cenozoic, but cannot be determined from the image. Layering and abundant fossil fragments indicate sedimentary deposition.

Uses & applications

Used as aggregate, cement and lime feedstock, building stone, and decorative stone; attractive fossiliferous pieces are collected or used for display.

Geological facts

The rounded inclusions are likely fossil shells or crinoid fragments preserved in a calcitic matrix. Differential weathering can make fossils stand out in relief.

Field identification & locations

Look for identifiable shell shapes, bedding, a relatively soft surface, and vigorous acid effervescence; common in marine sedimentary basins worldwide. Avoid confusing it with fossil-bearing marble, which has recrystallized textures and little visible porosity.