Diadumenian, as Caesar, AD.217-218. AR Denarius (19mm, 2.97g). Rome mint. 2nd emission of Macrinus, AD 217-218. Bareheaded, draped, and cuirassed bust right / Diadumenian standing left, holding signum and scepter; two signa to right. RIC IV 102 (Macrinus); Clay Issue 2; RSC 3b.