PART V. Planchet Errors:

Struck On ‘Aluminum’ Feeder Fingers

Definition: A coin that is struck on a feeder finger.  For U.S. coins, only aluminum or aluminum alloy feeder fingers are known to be involved.  World coins have been struck on feeder fingers of many different alloys.  U.S. coins are struck on “breakaway” feeder fingers that are designed to break off if struck by the dies.  Coins struck onfeeder fingers can represent a strike on what was an intact feeder finger or a strike on a feeder fingerfragment that broke off shortly before the strike was delivered

This 2007(?) John Madison dollar coin was struck twice on aluminum feeder fingers.