50 State Quarters to form what is known as a "mule". Only sixteen of these specimens, produced on dollar planchets, escaped from the mint. A 2005 Minnesota double die quarter, as well as a 2005 Minnesota quarter with extra trees (another die error), have both triggered numismatic interest. An unusual die break on some 2005 Kansas quarters created a humpback bison. Relatively more common are Kansas quarters bearing the motto "IN GOD WE RUST." The United States produces proof coinage in circulating base metal and, since 1992, in separately sold sets with the dimes, quarters, and half-dollars in silver. For the silver issues,
America the Beautiful Quarters the federal district, and each territory. The program is authorized by the America’s Beautiful National Parks Quarter Dollar Coin Act of 2008. Quarters will be issued depicting designs of national parks and sites in the order of which that park or site was deemed a national site. The quarters from three different states will depict parks or sites that were previously portrayed on the state quarters (Grand Canyon in Arizona, Yosemite in California, and Mount Rushmore in South Dakota). Though they will depict the same sites, they bear new designs. Of the 56 designs there are Beginning with the El