This Constantius I has a gilt obverse. It looks old, based on the deposits. Perhaps it was done in antiquity. Anyway, it is an oddity.
Constantius I
A.D. 296- 303
25x27mm 9.2gm
FL VAL CONSTANTIVS NOB C; laureate and cuirassed bust.
GENIO POPVLI ROMANI; Genius standing left, modius on head, naked but for chlamys over left shoulder, right holding patera, left cornucopiae.
RIC VI London 14a/20