Boucheron emerald and diamond ring. Set with a round old cut natural emerald to centre in a rubover setting with a weight of 0.15 carats, flanked by two curving rows of round brilliant cut diamonds in open back grain settings, fourteen in total with an approximate combined weight of 0.40 carats, to a circular cluster with an articulated scalloped and fluted yellow gold upper piece rotating to expose and cover the diamonds as preferred, flanked by heavy trumpeted shoulders to a solid D-shape shank. Marked 18 carat yellow gold, signed 'BOUCHERON', numbered 'B645 11471', 'OR 750', maker's mark, French, circa 1970s.