This unique 1974 Jefferson Nickel was struck on a struck 1973 Jefferson Nickel. It is still in the original 1974 Uncirculated Mint set. This incredible mint error was featured in the book, 100 Greatest U.S. Error Coins. In 2010 the authors valued this unique mint error from $15,000 to $17,500. There are only a few known U.S. coins with two different dates (dual dates) that were struck on previously struck coins of the same denomination.