By GovMint :
The U.S. Mint halted including silver in most circulating coins in 1965 through the Coin Act of 1965. This pivotal decision marked a significant shift in coin composition, transitioning from silver to less expensive metals like copper and nickel due to an ongoing shortage of silver at the time. Before 1965, many circulating coins, including dimes and quarters, were struck with 90% fine silver. Today, these coins are struck with a clad composition, meaning they have a core and outer layer made of different metals.
