This 1964 Washington quarter struck at the Denver Mint is the last struck in 90% silver! For 168 years, since 1796 when the U.S. Mint began striking quarters, they had been minted in 90% fine silver. In the early 1960s, demand for silver picked up, and a coin shortage developed in the U.S. So 1964 became the final year 90% silver coins were struck for circulation. Early Washington quarters are now in great demand by collectors, and where better to start than with the important 1964 issues – the last struck in 90% silver!