Prisoner's Coins

Prisoner's coins, known in English as prisoner's coins or carved coins , are ordinary coins that detainees would clandestinely transform into engraved, carved or repoussé objects. Deprived of proper tools, they used nails, metal shards or fish bones to incise portraits, genre scenes, allegorical figures or coded messages onto the surface of the metal. These objects circulated as tokens of affection, lucky charms or currency within prison walls. In France, their production is documented as early as the late 18th century in the bagnes of Brest, Rochefort and Toulon, and later in the colonial penitentiaries of French Guiana and New Caledonia until the early 20th century. Comparable examples exist in Great Britain, the United States and Australia, often associated with the major periods of incarceration throughout the 19th century.

The coins used are generally made of copper, bronze or low-grade silver — common five-centime pieces, one-sou coins or their foreign equivalents — sometimes complemented by bone, mother-of-pearl or thin tin appliqués. Certain exceptional pieces combine several techniques: intaglio engraving, repoussé and inlay work, bearing witness to skills acquired prior to incarceration, often those of engravers, goldsmiths or sailors.

For the collector, authenticity rests on several converging criteria: the legibility of the original coin beneath the engraving, the characteristic irregularity of the hand-worked line — entirely distinct from any mechanical production — a homogeneous patina firmly anchored in the recesses, and the absence of modern retouching. Signatures are rare but do exist; they may correspond to a prisoner's number rather than a name. Documented provenance, even partial, remains the most decisive criterion of value, followed by iconographic quality and the integrity of the monetary support.