First, the coin: Denomination: AR drachm? Obs: Unidentified; rev: Galloping horse to the left. Weight: 1.37g; Ø:1.6cm. For me, there are few discernable details: the observe shows, perhaps, a floral pattern, which is off-centered. Googleing 'Celtic floral pattern' however, gives many results, none of which have anything to do with coins. The reverse, showing a galloping horse to the left, is neither very helpfull. The seller stated "likely Helvetii Celts". Any help would be greatly appreciated.