The following Q&A is excerpted from Clifford Mishler’s Coins: Questions & Answers, 5th edition:
Q: I often hear people refer to the Eisenhower dollar as a silver dollar, but am wondering if that is correct terminology, as any circulated examples of this coin that I have encountered appear to be made of a similar metallic composition to that used for dimes, quarters, and halves?
A: Actually, that terminology could be considered technically correct, as the enabling legislation passed in 1970 stipulated the coin be minted of both silver and cupro-nickel clad copper, but with only the latter intended for circulation.
While Eisenhower dollars have the same physical diameter (38.1mm) as traditional silver dollars, they are somewhat lighter in both versions. The traditional silver dollars, minted from 1840 through 1935, were struck of .900 fine silver with a total weight of 26.73 grams, the pure silver weight of each being 0.77344 ounce. From 1971 through the 1975–1976 issue, the Eisenhower silver dollars were struck of a clad silver composite with a .400 fine silver content, the pure silver weight of each being 0.3161 ounce. The cupro-nickel clad Eisenhower dollars were minted from 1971 through 1978, the weight of these pieces being just 22.68 grams.
Silver versions of the Eisenhower dollar were struck and sold to collectors in both Uncirculated and Proof qualities. The silver Eisenhower dollar issues through 1975–1976 (Bicentennial) stand as the last hurrah of the Western Silver Lobby, their champion being Senator James McClure of Idaho.