The phrase "heads or tails" is as old as the coin flip. However, what if the coin has two heads and two tails (of the eagle)? This amazing error coin that is part of Heritage's August Auction combines several mistakes.
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. Next, the portrait as well as the reverse are widely doubled, allowing you to see two heads and two tails sides. 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.