In coin collecting, what is a proof?

A proof coin is a coin that has undergone a very specific and high-quality minting process. These coins are minted especially for collectors and usually sell for more than face value.

Historically speaking, a proof was made to check the individual die and for archival purposes. For a time, beginning in 1916, the United States stopped making proof coins. The act was picked up again in 1936.

Proof coins can be distinguished from regular coins by their sharper rims and smoother fields. Dies have also been polished in ways to create a mirror finish on the field, and chemicals are added to certain parts of the die to give the coin a frosted appearance.