This coin is a 1998 Jefferson Nickel, minted in San Francisco, denoted by the 'S' mint mark. It is part of the Jefferson Nickels series and serves as a proof version, which typically features a polished appearance and sharper details compared to standard strike coins. The denomination is 5 cents, commonly referred to as a nickel, with a composition of copper-nickel. The coin measures 21.2 mm in diameter and weighs 5 grams, adhering to the standard specifications for nickels in the United States. It has a mintage of 2,957,286, making it relatively common among collectors. However, as a proof coin, it is generally regarded as being of higher quality due to the minting process used. Overall, this 1998 San Francisco proof Jefferson Nickel reflects a rich history of American coinage and serves as a collectible item for numismatists and enthusiasts interested in U.S. currency. Its nominal face value is 0.05 USD, but its collectible value may vary based on its condition, presentation, and demand in the market.