Spotting cast and counterfeit coins

Seams, pimples, soapiness — the tells of a coin that was never struck.

A struck coin has flow lines — metal moved under the die, leaving crisp letter edges and a certain life in the surfaces. A cast copy replaces that with soapy softness: rounded letter bases, tiny raised pimples where air bubbled in the mould, and often a seam or filed line around the edge.

Weigh everything. Casts usually come in light, or in the wrong metal under a plated skin. Compare against published weights for the type; a denarius at 2.1 g needs explaining. Under magnification, look for uniform micro-pitting — mould texture — where you'd expect flow lines.

Some counterfeits are themselves antiquities: ancient forgers made plated cores, and 18th-century collectors bought 'Paduan' copies now collectable in their own right. So describe the evidence rather than passing judgement — 'cast seam visible at 3 o'clock, weight 15% light' — and mark the record honestly, possibly as a reproduction.

From the guide library inside Collectors Catalogues, a free app for cataloguing antiques and finds with honest, museum-grade records.

More on coins

Identifying coins — Portrait, legend, and strike.

Identifying tokens and jettons — Not quite coins.

Identifying Roman silver coins — Denarii, antoniniani, and siliquae — and how to tell them apart.

Identifying Roman bronze coins — From heavy sestertii to tiny late-Roman nummi.

Identifying Greek coins — City badges, gods, and fabric — reading coins struck before Rome ruled.

Identifying Celtic coins — Abstract horses, wreaths, and heads — coinage reimagined by Iron Age artists.

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