fossil

Fossil coral fragment

Probable scleractinian (stony) coral; calcite/aragonite replaced by calcite (identification uncertain from image)

AI-generated identification · may be incorrect

Pale brown-gray, porous, weathered specimen with apparent corallite cavities and a dull to slightly waxy luster. Hardness about 3–4 if calcitic; rhombohedral calcite cleavage may be present; specific gravity roughly 2.6–2.8.

Identified September 10, 2026More fossil →

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Physical properties

Formation & geological history

A colonial marine coral skeleton accumulated in a reef or shallow-water limestone and was later lithified and commonly mineral-replaced during diagenesis. Exact geological age cannot be determined visually; fossil corals range from Paleozoic to modern geological deposits.

Uses & applications

Primarily a teaching, display, and collecting specimen; fossil coral may also be cut and polished decoratively, but this small piece has little industrial value.

Geological facts

The cavities are former corallites—individual coral animal chambers—not vesicles from volcanic rock. A drop of dilute hydrochloric acid or vinegar may cause effervescence if exposed calcite is present.

Field identification & locations

Look for repeated polygonal or circular corallite patterns, unlike random volcanic pores; compare with known coral-fossil references because weathering obscures the structure. Common in uplifted reef limestones worldwide, including Florida, the Caribbean, Australia, and parts of Europe and Asia.