Dan - Up through 1964 US silver coinage was still 90% silver, plus
1965 Kennedy halves. Silver was de-monetized, and we went to
cupro-nickle coinage. There were NO silver dollars minted then. The
early 1970s saw the Eisenhower dollar, which even in presentation
pieces was a weird mix of clad metals which included silver.
Small Wonders Lapidary