What is a mint mark?
It’s impossible to give a simple description of where to look for a mint mark without knowing a coin’s date and denomination, and sometimes even that information isn’t enough. Mint marks are often worked into some inconspicuous place in the design, but in recent years the practice in more and more countries is to make the mint mark more obvious. For example, in 1968 the U.S. moved mint marks from the back sides of most coins to a more prominent place on the front; in the 1980s the size of the letters was increased making them even more visible.
