fossil

Fossil coral fragment

Likely scleractinian coral; calcium carbonate, predominantly aragonite or recrystallized calcite (CaCO₃)

AI-generated identification · may be incorrect

Tan, porous, irregular fragment with possible corallite cavities; Mohs hardness about 3–4, dull to earthy luster, and no obvious cleavage. Exact identification is limited by the small, weathered specimen and image quality.

Identified September 7, 2026More fossil →

Explore Fossil coral fragment 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 as a marine coral skeleton, later buried and fossilized through mineral preservation or replacement; age could range from Paleozoic to Cenozoic depending on locality. Common in uplifted reef limestones and coastal sedimentary deposits.

Uses & applications

Primarily a collecting and educational specimen; fossil coral may be cut and polished for decorative objects or jewelry. It is not typically used structurally as an isolated fragment.

Geological facts

Fossil coral can preserve repeating corallite patterns, honeycomb-like pores, or radial septa. A weak acid reaction supports carbonate composition, though testing should be done cautiously and only with permission.

Field identification & locations

Look for organized, repeated coral cups or honeycomb structure rather than random vesicles; limestone matrix and a vigorous dilute-HCl fizz are supportive clues. Common examples occur in reef limestones worldwide, including Florida, Indonesia, Australia, and the Caribbean.