Oscar Heyman Brothers sapphire and diamond screw ring. Set to centre with a single round old cut diamond in an open back claw setting with an approximate weight of 0.75 carats, encircled by eighteen tapered baguette cut diamonds in open back rubover settings with a combined weight of 1.00 carats, entwined with a further row of eighteen tapered baguette cut natural unenhanced sapphires with an approximate combined weight of 1.10 carats. The total approximate diamond weight is 1.75 carats, to a stepped circular ballerina cluster featuring polished borders, a structured openwork gallery and intricately pierced backholing, leading to split shoulders, flowing through to a solid ridged shank. Marked 18 carat yellow gold and platinum, maker's mark for Oscar Heyman Brothers, numbered '26389', American, circa 1960, accompanied by Oscar Heyman Brothers authenticity certificate.
