The story behind the coin
It is a "cent" with the wrong face. The front shows Liberty in a cap — the design from an 1818 quarter dollar. The back says ONE CENT in a wreath — the back of an 1818 large cent. Two coins of different value, mashed into one. And there is exactly one in the world.
A coin made from two dies that were never meant to go together is called a mule (after the cross-bred animal). Most mules are accidents — a tired press operator grabs the wrong die. This one was no accident.
In the late 1850s and early 1860s, the Philadelphia Mint had a quiet side business. Collecting was exploding, and Mint officials traded restrikes (coins struck later from old dies) and oddities to collectors in exchange for rarities the Mint's own cabinet was missing. It was, in the words of one numismatic writer, the era "when the Mint would make anything for anybody." This little silver cent is one of those somethings.