A cameo coin is a numismatic term for a type of coin. Here's what it means.
What is a cameo piece?
« En camée » se dit de l’aspect d’une pièce dont les coins utilisés pour sa fabrication ont déjà servi (et sont donc couverts de velours) et sont repolis.
Of course, this polishing only concerns the flat parts of the corners (i.e. the fields) and does not remove any of the velvet from the hollows (i.e. the coin's reliefs).
In the ideal state of a cameo coin, the reliefs are matt and velvet-covered, forming a pleasant contrast with the mirrored fields. There are, of course, many stages and degrees to this state, as the fields are re-covered with velvet.
Stamps for modern collectors, such as Belle Épreuve, imitate this appearance in an artificial way.


