As a general rule, modern proof error coins are scarce. There are several reasons for this. The requirements of special production hinder the number and types of errors that can occur. For one, during production of proof coinage, dies are frequently replaced and, therefore, many of the errors associated with late-state die failure seldom occur. Also, proof coins are placed into special packaging which means that any aberrantly shaped error coin will likely be discovered at the packaging stage. And last, the Mint employs an exceptionally high level of quality control surrounding the production of proof coinage.

NGC did, however, receive a Proof Presidential $1 error coin almost as soon as we began receiving submissions. Surprisingly, this was a relatively dramatic and scare type of error, a coin struck from nonparallel dies also called horizontally misaligned dies. This type of error occurs when the dies are not level with each other during striking. The result is a “wedge-shaped” coin. The misalignment also creates a gap between the collar and the dies. During striking, metal will flow into that gap forming an enlarged and distorted, raised rim or flange. A handful of similar errors of this type have been seen by NGC. Read Full Story

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