•    Error coins are some of the rarest numismatic items in existence as they are all one-of-a-kind 
•    This pair of coins are an example of a die cap 
•    In this pairing, the obverse Kennedy became stuck to the die, creating a cap 
•    As the minting press continued to strike, it forced the planchet up the press, creating the fold on the edge 
•    Additionally, these coins are part of a mated pair, doubling their rarity as both had to pass quality control and exit the mint facility