Doubled Die Mint Errors are one of the most misidentified mint errors. See pictures of this error to help identify. The most famous of Doubled Dies is the 1955 Lincoln Cent Double Die, but there are many.
1936 Canadian dot coins - Among the most valuable Canadian coins are the 1936 Canadian coin dot specimens. These coins are not only valuable in terms of market price but also of historical significance.
1914 D Lincoln Wheat Small One Cent 1c Penny Coin - Denver - Key Date