Blank – A blank of metal intended for coinage but never struck with the dies.
Broadstrike – A coin that was struck outside of the retaining collar.
Brockage – An error that reflects a mirror image of the design impressed on the opposite side of the same coin.
Clipped Planchet – An incomplete coin that is missing 10-25% of the metal.
Defective Die – A defective die will cause a coin to show raised metal or have a small rim break.
Lamination – A flaw with a fragment of metal peeled off the coin's surface.
Mule – A coin struck with two dies not meant to be used together.
Multiple Strike – A coin that has additional image from being struck again off center.
Off Center – A coin that has been struck out of collar and incorrectly centered with part of the design missing.
Overstrike – A new coin produced with a previously struck coin used as the planchet.
Wrong Planchet – A coin that is struck on a planchet designed for another denomination or metal.