fossil

Fossilized colonial coral

Tabulate coral, likely Favosites or a related genus

AI-generated identification · may be incorrect

A calcium-carbonate fossil showing tightly packed polygonal corallites and laminated growth bands; typically white to gray, dull to slightly waxy, Mohs hardness about 3–4, with no obvious cleavage. The honeycomb pattern is diagnostic of colonial coral.

Identified August 29, 2026More fossil →

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Physical properties

Formation & geological history

This is a Paleozoic marine fossil formed when colonies secreted calcite skeletons; burial and mineral replacement preserved the coral structure. Related tabulate corals are especially common in Silurian–Devonian rocks, roughly 443–359 million years old.

Uses & applications

Collected as a fossil, used in educational displays, lapidary items, and decorative carvings; it has little industrial value in small pieces.

Geological facts

Tabulate corals were colonial animals, not plants, and became extinct during the Permian–Triassic extinction. Individual corallites housed tiny polyps and collectively formed reef frameworks.

Field identification & locations

Identify it by the regular honeycomb or parallel corallite tubes, unlike irregular modern coral fragments; common sources include New York, Michigan, Ontario, the Baltic region, and Morocco. Avoid acid testing because calcite fizzes and the specimen may be damaged.