Art Deco diamond cluster ring. Set with three round old cut diamonds to centre in open back grain settings with a combined weight of 1.20 carats, further set with eighteen round old cut diamonds in open back grain settings with a combined weight of 0.75 carats. The total approximate diamond weight is 1.95 carats, to a geometric openwork cluster design featuring millegrain details, linear gallery, intricately pierced backholing, the raised stepped shoulders terminate to ribbed details before smoothing to a solid D-shape shank. Marked platinum, French, circa 1930.