fossil

Fossiliferous limestone

Bioclastic limestone, primarily calcite (CaCO₃), with possible shell or coral fossil molds

AI-generated identification · may be incorrect

Soft to moderately hard (Mohs 3), pale gray-beige, dull to slightly waxy luster, fine-grained carbonate matrix, and irregular fossil impressions or shell fragments. Calcite commonly effervesces strongly with dilute hydrochloric acid; it has no consistent cleavage in this massive form.

Identified August 19, 2026More fossil →

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 when marine shells, skeletal debris, or carbonate mud accumulated and lithified in shallow seas; the specimen may be Paleozoic–Cenozoic, but age cannot be determined from the image alone. Weathering has accentuated cavities and fossil relief.

Uses & applications

Used as aggregate, cement and lime feedstock, building stone, and decorative material; fossiliferous pieces are chiefly collected for educational and aesthetic value.

Geological facts

The raised and recessed patterns resemble weathered marine bioclasts, possibly shell fragments or coral, rather than a crystalline mineral. A precise fossil identification requires close examination of symmetry, internal structure, and matrix.

Field identification & locations

Common in former marine sedimentary basins worldwide, including Florida, the Alps, the Mediterranean, and many Paleozoic limestone regions. Confirm with acid fizz and inspect with a hand lens; avoid acid testing if preservation is important.