Quarters minted in 1964 are the last standard quarters made of 90 percent silver and 10 percent copper. In 1964, the U.S. government switched to a 75 percent copper and 25 percent nickel alloy as a response to the rising commodity price of silver.
Quarters minted in 1964 or earlier contain about $3.50 worth of silver, based on the average 2014 price of silver per ounce. Proof coins minted for commemorative purposes still contain 90 percent silver and are valued at higher than their 25-cent face value. The edges of silver quarters are completely silver, while quarters made of copper and nickel have a copper-colored band on their edge.