Collectible coins, including Proof Sets from the United States, are specially minted coins produced for collectors rather than general circulation. The 1991 Proof Set includes a selection of coins struck with a high-quality finish, featuring clarity and detail due to the special preparation of the dies used in minting. These sets typically contain the 1 cent coin (1c), along with other denominations such as the nickel, dime, quarter, and half dollar, all encapsulated in a protective case to preserve their condition. Proof coins are characterized by their mirror-like surfaces and are often sought after by numismatists for their aesthetic appeal and potential investment value.

Item Denomination Series Year Mint
1991-S 1c-$1 Prestige Proof Set 1c-$1 Proof Sets 1991 San Francisco