I found a 1978 no mint mark dime. Are they rare and how much are they worth? I can't seem to find anything about it on the web. I know for a fact that it is not a proof. So i don't know if it's worth anything or not or how rare it is? I will try to put some pictures up in a little. I also found a identical 1978 d but that one does have a mint mark. They look exactly the same but the one does not have a mint mark.