fossil

Fossil coral

Likely colonial rugose coral (e.g., Lithostrotion or Hexagonaria), replaced by calcite

AI-generated identification · may be incorrect

Gray-beige, weathered limestone-like specimen with radiating corallite structures; calcite hardness ~3, vitreous to dull luster, rhombohedral cleavage, specific gravity ~2.7. The repeated starburst chambers are diagnostic of fossil coral.

Identified September 9, 2026More fossil →

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Physical properties

Formation & geological history

A marine colonial coral skeleton was buried in carbonate sediment and mineralized or preserved as limestone, commonly during the Paleozoic (about 541–252 million years ago). Exact age and genus require locality and closer examination.

Uses & applications

Primarily a collectible and educational fossil; polished fossil coral is used for ornaments and jewelry, though this small rough piece has little commercial utility.

Geological facts

The apparent “flower” pattern consists of individual coral cups (corallites), showing the colony’s growth structure rather than crystal formation.

Field identification & locations

Look for repeated radial septa or honeycomb-like chambers across broken surfaces; dilute acid may fizz because of calcite, but testing can damage it. Common in Paleozoic carbonate rocks worldwide, especially North America and Europe.