sedimentary

Fossiliferous limestone

Bioclastic limestone, primarily calcite (CaCO₃)

AI-generated identification · may be incorrect

Typically gray-beige, fine to medium grained, with visible fossil fragments, cavities, and brown iron-oxide staining; dull to subtly crystalline luster. Calcite hardness is Mohs 3, with good rhombohedral cleavage; it effervesces strongly in dilute hydrochloric acid.

Identified August 16, 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 from lithified marine shell, coral, or skeletal debris in shallow seas; the pictured specimen may be Paleozoic to Cenozoic, but exact age requires locality and fossil identification. Burial compaction and calcite cementation produced the solid rock.

Uses & applications

Used for aggregate, cement, lime, building stone, and occasionally decorative or fossil-display specimens. Rough collector pieces commonly sell for about $5–$30; unusually well-preserved fossils or attractive polished examples may bring $50–$200.

Geological facts

The irregular holes and raised patterns likely represent dissolved or preserved bioclasts, burrows, or coral-like structures rather than mineral crystals. Iron staining accounts for the tan-brown coloration.

Field identification & locations

Identify by its sedimentary layering, fossil textures, relatively soft surface, and acid fizz; a steel nail may scratch it. Common worldwide in former marine basins, including Europe, North America, and Asia.