That's an AE drachm from Elymais. I don't have my reference book at hand, but I think the ruler is Kamnaskires-Orodes, early–mid 2nd century AD. Here are two of my Elymaean drachms: Kingdom of Elymais, Orodes II, early to mid 2nd c. AD, AE Drachm. Obv: Bearded bust of Orodes facing, wearing tiara, no large hair tufts at sides; to right, pellet in crescent and anchor with two crossbars. Rev: dashes. Ref: van't Haaff 13.3.2–1B. 15 mm, 4g. Kingdom of Elymais, Orodes V, late 2nd–early 3rd c. AD, AE Drachm. Obv: Bearded bust of Orodes left with double diadem and tuft of hair on top of head. Rev: Bust of Artemis with beaded tiara left. Ref: van't Haaff 18.1.1-2A. 13 mm, 2.6g.