The composition of United States quarters underwent a significant change in 1965. Prior to this year, circulating quarters were composed of 90% silver and 10% copper. This gave the coins intrinsic value tied to the fluctuating price of silver.
The increasing cost of silver, coupled with a rising demand for coinage, prompted the U.S. Mint to eliminate silver from circulating dimes and quarters. This transition was implemented to reduce production costs and maintain an adequate supply of coinage for commerce. The removal of silver also stabilized the monetary system by reducing the impact of silver market volatility on coin production.