sedimentary / fossil

Fossiliferous Limestone / Coral Fossil

Fossiliferous Limestone with Anthozoa (Coral) fossil

AI-generated identification · may be incorrect

Hardness: 3-4 (calcite base), Color: Grey, tan, brown, Luster: Dull to earthy, Structure: Massive with embedded fossils, Specific Gravity: ~2.5-2.7

Identified August 25, 2026More sedimentary / fossil →

Explore Fossiliferous Limestone / Coral Fossil in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 3-4 (calcite base), Color: Grey, tan, brown, Luster: Dull to earthy, Structure: Massive with embedded fossils, Specific Gravity: ~2.5-2.7

Formation & geological history

Formed in shallow marine environments where coral reefs and other calcium carbonate secreting organisms lived and died, later lithified into limestone. Often Devonian to Carboniferous in age.

Uses & applications

Collectible for fossil enthusiasts; sometimes polished for ornamental use. Limestone is widely used in construction and cement.

Geological facts

This specimen appears to contain a colonial rugose or tabulate coral fossil, common in Paleozoic marine deposits. The central dark area might be a cavity filled with secondary minerals or matrix.

Field identification & locations

Look for distinct structural patterns of marine life (like the radiating lines of coral polyps) within a softer sedimentary matrix. Commonly found in areas that were once ancient shallow seas, such as the Midwestern US.