fossil

Fossilized coral (likely honeycomb or branching coral)

Fossil coral; probable Scleractinia or Tabulata, composition mainly microcrystalline CaCO₃

AI-generated identification · may be incorrect

Brown, gray, and cream porous specimen with polygonal-to-irregular corallite cavities; dull to slightly waxy luster, hardness about 3–4 Mohs, and no obvious cleavage. The cavities are natural coral structures, partly filled or weathered.

Identified August 10, 2026More fossil →

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Physical properties

Formation & geological history

A colonial marine coral skeleton was buried and mineralized, commonly through replacement or infilling by calcite, silica, or iron-bearing minerals. The exact geological age cannot be determined from the image; fossil corals range from Paleozoic to recent deposits.

Uses & applications

Collected as a fossil and used for educational displays, lapidary pieces, cabochons, and decorative carvings; it is generally not suitable for structural construction.

Geological facts

The repeated holes are corallites—individual chambers occupied by coral polyps—not ordinary vesicles in volcanic rock. Brown coloration commonly results from iron oxides or organic mineral staining.

Field identification & locations

Identify by its repeated coralite pattern, curved colony growth, carbonate response to dilute acid, and relatively soft surface; avoid acid testing if preservation matters. Fossil coral occurs in ancient reef limestones worldwide, including Florida, Michigan, Indonesia, and Australia.