Choose a Mint Error Category Below Missing Edge Lettering Two-Headed Coins Two-Tailed Coins Experimental Strikes Martha Washington Test Pieces Brockages Capped Dies Counterbrockages Die Adjustment Strikes Double/Multiple Strikes Double Denomination Hub Trials and Die Trials Mated Pairs Mules Off-Center Struck Coins Overstrikes Spectacular Errors Transitional Errors Uniface Strikes Uniface Die Trials Wrong Planchet / Off-Metal