I have decided I need to authenticate a coin, an Athenian Didrachma. In looking up the authentication of ancient coins I have discovered that NGC does not actually offer a guaranteed authentication of ancient coins and I am not interested in the grading aspect which they offer. Apparently David Sear does, if he is still doing this kind of service (anybody know?) but I am not certain that he is. Is there another service that does authenticate ancients? I don't want drop $50 or $60 into an authentication service that has no real credence or value. Thanks for any info you can give me.