I actually
posted a slightly larger (and slightly newer) Mysia hemiobol a few days ago.
It was
not, as it happens, the smallest coin in my collection (that title goes, as far as I can tell, to a silver kopek of Peter the Great - not the one posted
over here, which is actually a bit larger, but a very similar one from 1709 that I hadn't seen in several years).
I still want to get a smaller one sometime (preferably another Greek fraction, but I probably couldn't afford that).
My extreme nearsightedness actually makes appreciating such tiny coins much easier (just need to take my glasses off), and there's even actually a theory that the Greeks used nearsighted mint workers to make them originally.