It features the obverse of a Washington state quarter and the reverse of a Sacagawea dollar. This coin was struck on a Sacagawea dollar planchet. The mint confirmed in July 2000 that the coin was a legitimate error, created by the accidental replacement of a cracked Sacagawea obverse die with a Washington obverse die. Several thousand of the coins were reported to have been minted before the error was discovered, and mint employees recovered and destroyed most of them. As of May 2019, 18 are publicly known to exist and have been certified, of which 14 are owned by Tommy Bolack. A specimen was sold in August 2012 for $155,250. "Handsome" mules Sometimes mints use proof dies in the production of coins intended for circulation. Coins produced when an identifiable proof die is "married" with a business die are known as "handsome" mules. The details on handsome mules are often noticeably sharper, and thus are distinguishable from ordinary business strikes in circulation. References External links Coins Mint-made errors