Mint Silver Proof Coin Sets from 1998 through 2017, along with the 1992, 1993, 1995, and 1996 sets, come with a Certificate of Authenticity from the U. These uncirculated coin sets are composed of silver, copper-nickel, copper-plated zinc, and manganese-brass, making them high-quality collector’s items. Each set includes coins struck in proof condition at the San Francisco Mint, showcasing the craftsmanship and precision of the U.