A vintage opal and diamond cocktail ring, featuring an oval cabochon semi black solid opal (16.12 x 12.44 x 7.42 mm) of mostly violet to yellow colours, to surround of 20 round brilliant cut diamonds totalling approx. 0.90ct in white gold basket mount to plain gold shank, top 21 x 17 mm, size O, wt. 7.56g.