fossil

Fossilized coral fragment

Likely fossil coral (Scleractinia or Tabulata), replaced or preserved as calcium carbonate (CaCO₃)

AI-generated identification · may be incorrect

Cream-white, porous honeycomb texture with numerous corallite holes; typically calcite/aragonite, Mohs hardness 3–4, dull to slightly vitreous luster, and no obvious cleavage. The irregular branching form is characteristic of coral rather than a crystalline mineral.

Identified September 6, 2026More fossil →

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Physical properties

Formation & geological history

Coral colonies formed in shallow, warm marine reefs; the specimen was later buried and preserved through mineralization or recrystallization. Its precise geological age cannot be determined from the image, but fossil corals range from Paleozoic to modern deposits.

Uses & applications

Primarily a teaching, collecting, and decorative specimen; fossil coral is occasionally polished for jewelry, though this fragment appears natural and unpolished.

Geological facts

The holes are individual corallites—the skeletal cups that housed coral polyps—not ordinary weathering cavities. Some fossil corals are excellent indicators of ancient shallow tropical seas.

Field identification & locations

Identify it by the repeated polygonal or circular corallite pattern and carbonate softness; vinegar may weakly fizz on a fresh surface, though testing can damage it. Common in limestone and reef deposits worldwide, including Florida, Michigan, Australia, and parts of the Caribbean.