fossil

Fossilized coral (likely colonial/rugose coral)

Replaced or permineralized coral skeleton, commonly calcite (CaCO₃); exact taxon cannot be confirmed from one photo

AI-generated identification · may be incorrect

Tan-gray, porous, irregular skeletal texture with numerous corallite cavities; dull to slightly earthy luster, Mohs hardness about 3 (calcite), commonly reacts strongly with dilute hydrochloric acid, and has no obvious cleavage.

Identified September 6, 2026More fossil →

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Physical properties

Formation & geological history

A colonial marine coral skeleton was buried in carbonate sediment and later permineralized or recrystallized, probably during Paleozoic–Mesozoic marine deposition; the age and preservation process require locality or laboratory testing.

Uses & applications

Primarily a collector and educational specimen; polished fossil coral is occasionally used for décor and cabochons, but porous material is generally unsuitable for high-value jewelry.

Geological facts

The cavities represent individual coralites or corallite walls, not vesicles from volcanic rock. Weathering can enlarge the pores and obscure the original coral growth pattern.

Field identification & locations

Look for repeated polygonal or radial coral-cell structures and acid reaction; common sources include limestone exposures in the Great Lakes region, Texas, Florida, Australia, and Madagascar. Value is typically $10–$75 for a common hand specimen, or $100–$300+ if unusually large, attractive, and well identified.