fossil

Fossil ammonite

Ammonoidea; likely a chambered ammonite mold/cast

AI-generated identification · may be incorrect

Gray-brown, weathered, and low-luster with rounded chamber-like whorls and possible suture lines; commonly calcite/aragonite replaced by calcite or preserved as a limestone mold. Hardness is approximately 3–4 if calcitic, with indistinct cleavage and specific gravity around 2.6–2.8.

Identified September 18, 2026More fossil →

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Physical properties

Formation & geological history

Ammonites were extinct marine cephalopods that lived from the Devonian to the end-Cretaceous, about 409–66 million years ago. This specimen likely formed when the shell was buried in marine sediment and later mineralized or dissolved to leave a cast.

Uses & applications

Primarily used for education, collecting, and decorative display; polished ammonites may be sold as gemstones or ornamental pieces.

Geological facts

The visible coiled form represents the animal’s partitioned shell, whose internal chambers controlled buoyancy. Exact species and age require clearer views of the coil and suture pattern, plus locality information.

Field identification & locations

Look for a planispiral coil, repeated chambers, and radiating or branching sutures; common sources include Morocco, Madagascar, England, Germany, and Alberta. The image appears fossiliferous, though preservation is heavily weathered.