Roman Ring with Portrait Gemstone

1st-2nd century AD. A bronze ring with flat-section expanding hoop, inset carnelian intaglio engraved with a helmetted legionnaire's bust, the plumed helmet with a neck and brow guard. 4.29 grams, 23.5mm overall, 17.2x19.2mm internal diameter (approximate size British O, USA 7, Europe 14.98, Japan 14) (1"). From a late 1990s private collection; formerly acquired on the UK art market in the early 1980s.
Condition Report: Fine condition.