United States coins have been circulating for over 227 years since the first official coins were struck after the Mint Act of 1792 was signed by George Washington. American coins are among the most popular and widely collected coins in the world. When it comes to collecting U.S. Mint coins, there are some things to keep in mind. One is the type of finish on the coin: proof, reverse proof, and burnished, amongst other special finishes.. There is also the circulated or uncirculated status of the coin as well as the quality or grading of the coin. Lastly, the mintage or quantity of a coin must be considered when beginning a collection and seeking out specific specimens.