The 2026 S Silver Proof Set U.S. Mint 250th Semiquincentennial is a collection of uncirculated 25 cent coins struck in proof quality silver with a fineness of 0.999. Minted in San Francisco, these coins are part of the U.S. Mint's commemoration of its 250th anniversary. Each coin is certified as uncertified and holds a special designation as part of the 26RH series. This set is a valuable addition to any coin collector's portfolio, showcasing the craftsmanship and history of American coinage.