ROMAN STONE RING WITH VENUS CAMEO

1st century AD. A jet(?) finger ring with applied marble intaglio mask of Venus framed by locks of curled hair. 19.3 grams, 44.51mm overall, 18.87mm internal diameter (approximate size British R, USA 8 1/2, Europe 18 3/4, Japan 18) (1 3/4"). Property of a London lady; from her family collection formed in the 1970s. Fine condition.