fossil

Fossilized coral or porous marine limestone

Likely fossil coral (Scleractinia), composed mainly of calcite/aragonite (CaCO₃)

AI-generated identification · may be incorrect

Cream to pink, very porous, dull to slightly waxy luster, with rounded cavities and possible coral-like structures. Hardness about 3–4 Mohs; no obvious cleavage; specific gravity roughly 2.6–2.8 if limestone/coral.

Identified August 10, 2026More fossil →

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Physical properties

Formation & geological history

Likely formed as a marine coral skeleton, later buried and mineralized, or possibly a naturally weathered piece of porous limestone. Exact geological age cannot be determined from the photograph; beach specimens may be modern coral or older fossil material.

Uses & applications

Used mainly as a collectible or educational specimen; fossil coral and limestone can be cut or polished for ornaments, but this small piece has little practical industrial value.

Geological facts

The large openings may be eroded coral corallites, but their irregular shape also fits beach-worn limestone. A drop of dilute vinegar should fizz if it is carbonate material.

Field identification & locations

Common around tropical and subtropical coasts, especially coral-bearing shorelines. Check for repeated polygonal coral cells under magnification; a uniform honeycomb pattern supports fossil coral, while random pores suggest limestone or shell debris. Do not collect live coral or specimens from protected beaches.