A planchet English: /ˈplæntʃət/ is a round metal disk that is ready to be struck as a coin.
An unusual method was used to mint the one-sided, bowl-shaped pfennigs of the Holy Roman Empire.
The curved shape of the pfennig was very useful for handling small change because it was easier to grip than a flat coin.
These flat rolls or sheets of metal are then punched out into round blanks that are a little larger than the coin being struck.
Occasionally, blank planchets can be rare and valuable, such is the case for Morgan Dollar blank planchets, although authentication and appraisal by a coin grading service is highly recommended for such pieces as they would be fairly easy to counterfeit.