United States quarters minted in 1964 and earlier years consisted of 90% silver and 10% copper. These coins are often sought after for their precious metal content. However, a change occurred mid-way through the 1960s.
The rising price of silver led the United States Mint to discontinue using silver in circulating coinage. This decision was driven by economic factors, including the increasing cost of silver exceeding the face value of the coins. The transition aimed to stabilize the coinage system.