Finally, I've got this tiny little fellow--9 mm, ~0.85g.--that I haven't had much luck with so far (although it's been only 3 days). I've trying searching for different combinations of Greek AE, Athena, crescent, 9mm and IM (the reverse is IM within a crescent or semi-circle, although it looks like ΠM in the photo) on acsearch but haven't found anything yet. Any leads or suggestions?
Thank you, TIF. I checked Sigeion in ACSearch and didn't find a match, but then I checked Wildwinds and found this: Troas, Sigeion, AE9, ca. 350 BC. 0.88 g. Helmeted bust of Athena right SI-GE, crescent. BMC 20-21; SNG copenhagen 499; Klein 320; SNG Turkey I (Kayhan), 79; SNG Munich 318. With permission of Münzen & Medaillen (DE) GmbH - Auction 17, Lot 809, Oct. 2005. Looks like my coin (only much nicer!).