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.