Seleukid King Antiochos Hieras

Most likely a coin from Antiochos Hierax (246-227 B.C.). Ob: diademed head of Antiochus I, r., with wing above ear. Rx: Naked Apollo seated l. on omphalos stone (center of the world), holding arrow and resting on bow, Greek word on both sides. The grazing horse below indicates a mint in Alexander Troas (area of ancient Troy).
Weight is ~ 6.5 gm, and therefore does not conform to weight standards for a tetradrachm or a drachm (~21mm). Opinion of one expert is that certain design features do not conform to an authentic piece. While it's a nice execution you would have to say its a fake.
From CNG TRITON XXII, Lot 303: SELEUKID EMPIRE. Antiochos Hierax. Circa 242-227 BC. AR Tetradrachm (29mm, 17.00 g, 2h). Alexandreia Troas mint, Workshop A. Series I, Group A. Head right, wearing winged diadem / BAΣIΛEΩΣ ANT-IOXOY, Apollo Delphios, nude, testing arrow in his right hand, left hand holding tip of bow set on ground to right, seated left on omphalos; monogram to inner right; in exergue, horse grazing left and monogram. SC 875.1 var. (monogram in exergue); ESM 1568 var. (same); CSE –; SNG Spaer –; HGC 9, 399g. EF, lightly toned. Lovely high relief portrait. Unpublished variety
Articles to VIEW and DOWNLOAD:
An excellent article that features a story about the discovery of the only known living portrait coin that shows the image of lifetime portrait of Alexander the Great (not Herakles)is linked below. It's a MUST read!
Ptolemy's Egypt & Alexander's Portrait - Holt: Ptolemy's Egypt & Alexander's Portrait - Holt
Here's a very informative & illustrated paper on "The Spread of Coins in the Hellenistic World" by A. Meadows: Coins in the Hellenistic World A Meadows
Hellenistic Coin Portraiture - Sheedy: Hellenistic Coin Portraiture - Sheedy
Seleukid Coins Online page with authentic types at this: http://numismatics.org/sco/results?q=&start=900