fossil

Polished fossil ammonite slice

Ammonoidea (commonly polished juvenile ammonite or nautiloid-like cephalopod fossil)

AI-generated identification · may be incorrect

Fossilized chambered shell in tan, cream, and brown tones, likely preserved in limestone or silica-rich material; hardness about 3–6 depending on matrix, with dull to waxy polish. The radial septa/chambers form the sunburst pattern; cleavage is absent or indistinct.

Identified August 18, 2026More fossil →

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Physical properties

Formation & geological history

Ammonites were marine cephalopods that lived from the Devonian to the end-Cretaceous, becoming extinct about 66 million years ago. Their shells were buried in marine sediment and mineralized, then cut and polished by humans.

Uses & applications

Primarily used as a decorative, educational, or collectible specimen; polished slices are sold as curios and fossil art. Value is usually modest unless exceptionally large, well-preserved, or from a notable locality.

Geological facts

The visible radial divisions are internal shell chambers, not crystal growth. The painted or inked face appears human-added and is not part of the fossil.

Field identification & locations

Identify by the repeated chamber partitions and curved shell geometry; common sources include Morocco, Madagascar, Canada, and Germany. Estimated value: $5–$30 for a small polished slice, or $30–$100+ for larger, better-preserved examples.