100 times fewer Proofs were struck than circulation grade State Quarters, making these State Quarter Proofs must-haves. U.S. Proof coins are extraordinarily brilliant, with sharp relief and a mirror-like background. Their frosted, sculpted foregrounds give them a special cameo effect. Proof blanks are specially treated, polished and cleaned to ensure high quality strikes. The coins are then packaged in a presentation case to showcase and maintain their exceptional finish.