which quarters are made of silver

[Helen]

Based on the provided information, United States quarters minted for general circulation in the year 1964 and prior are composed of 90% silver. This includes the Washington Quarter series from its inception in 1932 through 1964. These coins are often referred to by numismatists and investors as "junk silver," a term that denotes silver coins in average circulated condition with no collectible value beyond their precious metal content.

The composition of the U.S. quarter changed due to the Coinage Act of 1965. Rising silver prices in the early 1960s caused the intrinsic metallic value of these coins to exceed their face value, leading the government to transition to a more cost-effective copper-nickel clad composition for circulating coinage beginning in 1965.

It is important to note, however, that the U.S. Mint has produced special silver quarters for collectors since the end of this period. Beginning in 1992, the U.S. Mint began issuing special silver proof sets containing dimes, quarters, and half dollars struck with the traditional 90% silver composition. These coins are not intended for general circulation but are minted specifically for the numismatic market. Additionally, other modern silver quarter issues exist, such as the 5 oz silver bullion versions from the America the Beautiful series.