fossil

Polished fossil ammonite pendant

Ammonite fossil, commonly a heteromorph or planispiral ammonoid; chamber walls are calcite-replaced aragonite

AI-generated identification · may be incorrect

Brown, highly polished, patterned shell with visible septal/chamber structure and a drilled hole; hardness about 3–4 (calcite), vitreous to waxy luster, dense carbonate composition. The dark brown material may include calcite, aragonite, pyrite, and matrix.

Identified August 27, 2026More fossil →

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At a glance

Common name: Polished fossil ammonite pendant
Scientific name: Ammonite fossil, commonly a heteromorph or planispiral ammonoid; chamber walls are calcite-replaced aragonite
Category: fossil
Identified: August 27, 2026
Method: Standard

AI Estimated Value

About $15–$60 for a common polished pendant; $75–$200+ for larger, exceptionally patterned, or scientifically identifiable specimens.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Ammonites were marine cephalopods that lived from the Devonian to the end-Cretaceous, roughly 400–66 million years ago. Their shells were buried in marine sediment and later mineralized, commonly during diagenesis.

Uses & applications

Used as jewelry and a collectible fossil; not generally used industrially or in construction. Polishing exposes the internal chamber patterns and increases decorative value.

Geological facts

The visible chambers are separated by septa, and the original shell material is often replaced by calcite or other minerals. Exact species and age cannot be determined confidently from this photograph.

Field identification & locations

Identify it by the chambered, septate shell pattern rather than ordinary mineral banding; common commercial material comes from Morocco, Madagascar, Russia, and Canada. Avoid acids, which can etch carbonate fossils.