You are right, there are Ike Dollars that are of 40% silver, but was not meant for and never used in circulation. The ones being circulated are clad, and whenever I remember, I ask for the teller to give me whatever they have. I love the Ike Dollars. Thus many do not consider it a "true US SILVER Dollar", and only the three (Seated Liberty, Morgan and Peace Dollar) are. BTW, I have a collection of the Eisenhower Dollars 1971-1978. Check it out, @underground!