What are US quarters made of?

Answer 1

Up till 1964, U.S. quarters (as well as dimes and half dollars) were struck in an alloy of 90% silver and 10% copper.

In 1964 the price of silver increased to the point where quarters contained much more than 25¢ worth of silver. Starting in 1965, quarters and dimes were made of a 3-layer "sandwich" consisting of a pure copper core with outer cladding of 25% nickel and 75% copper, for a total of about 92% copper, 8% nickel.

Note about half-dollars and dollars : From 1965 to 1969 half-dollars were made of 40% silver. They weren't made for circulation in 1970. In 1971 half dollars were converted to the same sandwich metal as dimes and quarters. Dollars were also made from copper-nickel until 2000, when the current gold-colored brass metal was used.