Worlds Smallest Coin?

Ye'll be wanting this page, then.

The smallest denomination recorded in the Greek system is the hemitartemorion, or 1/8th obol, weighing 0.09 grams - which equates to 1/48th of a drachm or 1/192nd of a tetradrachm. Or, to wrench it completely out of its proper historical context, not quite three "Widow's Mites", or enough silver to make a pre-1964 US silver coin with a face value of 0.36 US cents.

I suspect these teensy tiny ancient silver coins are actually commoner than prices and current availability would indicate. The trouble is, these things are just too darned small - they can't be detected easily with a metal detector and they'll fall straight through an archaeologist's sieve.

Smallest gold coin would be the fanam you have already seen, unless a 1/48th stater from Lydia minted by Croisos is smaller. Smallest silver would be the fractional obols, if you go by diameter, or my Norwegian bracteat if you go by weight. As for current coins, it is easy. No country use silver or gold for circulating currency anymore, only commems.