A major "oops" moment at the US Mint in the 1970s will result in a serious prize for collectors today. This 1973-S Proof Eisenhower Dollar, offered as part of Heritage's September US Coins Auction #1319, has a striking appearance that instantly tells you this that is a special piece and not like any other dollar coin of the period.

Proof coins are supposed to be struck to the highest standards of perfection when created by the US Mint. They are intended for Proof Sets, special collector's sets that never go into circulation. However, this proof coin really went astray when it was made and somehow escaped quality control to be available for error coin collectors today.

First, this is supposed to be a dollar but was struck on a Half Dollar planchet (a much smaller coin blank meant for the Kennedy Half Dollars made that year). Next, the coin has an off-center appearance because the smaller planchet was not big enough to evenly accommodate the whole design. Dollar-sized error coins are popular because you can really see the mistakes and appreciate them. Also, error coins are generally more valuable when you can read the entire date, so this coin is made more desirable by being able to clearly see that it is a 1973-S Proof.

We recently sold another 1973-S error for around $19,000, so this coin should draw lots of attention when it comes up for bid!

Images Courtesy of Heritage Auctions, HA.com

1973-S Eisenhower Dollar -- Struck on a Half Dollar Planchet
PR67 Cameo NGC