fossil

Fossilized coral (likely colonial coral)

Fossil scleractinian coral; possibly *Thamnasteria* or a related coral

AI-generated identification · may be incorrect

Gray-brown, weathered limestone-like specimen with numerous corallite pits; composed mainly of recrystallized calcium carbonate (calcite/aragonite). Hardness is about 3–4 Mohs, dull to slightly earthy luster, and no obvious cleavage; the porous holes are fossil coral structures rather than vesicles.

Identified August 18, 2026More fossil →

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Physical properties

Formation & geological history

A marine coral colony accumulated as a reef or carbonate deposit, was buried, lithified, and commonly recrystallized during diagenesis. Exact age cannot be determined from the image; fossil corals range from Paleozoic to Cenozoic deposits.

Uses & applications

Primarily a collectible and educational fossil; fossil coral may be cut and polished for ornamental objects or jewelry, though it is generally less valuable than gem-quality coral.

Geological facts

The pits represent individual corallites, the chambers occupied by polyps. Unlike volcanic pumice, the holes are arranged in biological patterns and occur in a carbonate-rich matrix.

Field identification & locations

Identify it by repeated polygonal or circular corallites, carbonate hardness, and lack of glassy volcanic texture; vinegar may weakly fizz on a fresh surface. Common in ancient reef limestones worldwide, including Florida, the Caribbean, Australia, and parts of Europe and Asia.