Diadumenian (217-218).     AE As, Rome mint, 217-218.   Obv.    M OPEL DIADVMENIANVS CAES. Bare-headed and draped bust right.        Rev.   PRINC IVVENTVTIS S C. Diadumenian, standing front, head right, holding standard in right hand and sceptre in left hand; on right, two standards.     RIC IV  216; C. 13.     10.88 g.   27 mm.      R.  Rare issue. Dark green patina. Rough surfaces. Smoothed.    About VF.