A proof coin is made using a special minting process that results in especially high-quality coins. Proof coins aren't meant for general circulation; they are made for collectors. The proof process has been improved through the years, and one of the features of modern proof coin technology is the cameo portrait.
The cameo portrait, (often just called the "cameo"), has a frosted, matte finish that stands out in sharp contrast to the highly-polished, shiny surface of the field. Proof coins haven't always been made this way, so keep in mind that not all proof coins will have a cameo, but all proof coins should have pristine, shiny, mirror-like surfaces and clean, bold designs.
The same coins that have reeded edges on their normal, circulating versions will have reeded edges on their proofs. All U.S. coins, proof or circulating, also have a rim. The technical term for this rim is the upset rim because when the coins go through the minting process, the rim is created by the "upsetting" machine. This really just means that the rim is set upward from the surface of the coin, but now you know a highly technical term to impress your fellow collectors with!
