when was the us dollar backed by silver
History of the United States dollar United States silver certificates were a type of representative money printed from 1878 to 1964 in the United States as part of its circulation of paper currency.[16] They were produced in response to silver agitation by citizens who were angered by the Fourth Coinage Act, and were used alongside the gold-based dollar notes. The silver certificates were initially redeemable in the same face value of silver dollar coins, and later in raw silver bullion.
Half dollar (United States coin) By the early 1960s, the rising price of silver was nearing the point where the bullion value of U.S. silver coins would exceed face value. In 1965, the U.S. introduced layered composition coins made of a copper core laminated between two cupronickel outer faces. The silver content of dimes and quarters was eliminated, but the Kennedy half dollar composition still contained silver (reduced from 90 to 40 percent) from 1965 to 1970.