Mint Errors Page



Proof coins are struck by technicians who hand feed the blanks into special presses. They are  produced, examined, and packaged using extreme quality control. It is very unusual to find major  proof errors. A
few broadstrikes, off centers, double strikes in collars and off-metals  have been known to be found in sealed proof sets. Proof errors are aggressively sought after by many error collectors.

Images courtesy of Byers Numismatic Corp.

Significant examples:
(1969-S) Washington Quarter Dollar (illustrated above) struck in conjunction with a Capped Die.  Discovered in a sealed 1969-S Proof Set.

Sources and/or recommended reading: