Diadumenian. As Caesar, AD 217-218. AR Antoninianus (23mm, 5.40 g, 7h). Rome mint. 1st emission of Macrinus, May AD 217. Radiate, draped, and cuirassed bust right / Diadumenian standing left, holding baton and scepter; two signa to right. RIC IV 106; Clay Issue 1; RSC 11. Good VF, surfaces a bit granular, slightly clashed obverse die. Rare denomination for Diadumenian.