Colombian emerald and diamond ring, circa 1970.

Colombian emerald and diamond ring. Set to centre with an octagonal emerald-cut natural Colombian emerald with minor oil in an open back half-rubover setting with an approximate weight of 0.90 carats, flanked by two round transitional cut diamonds in open back claw settings with a combined approximate weight of 1.30 carats, further set with two tapering baguette cut diamonds in open back half rubover settings with a combined weight of 0.20 carats, and framed to top and bottom with twenty-two square step-cut diamonds in open back channel settings with a combined weight of 1.30 carats. The total approximate diamond weight is 2.80 carats, to an impressive three stone cluster ring featuring polished edges, a linear pierced gallery and fancy shape open backholing, leading to tapering shoulders which flow through to a solid flat shank. Marked 18 carat yellow gold, signed 'Nava Encini', accompanied by Instituto Gemmologico Cisgem report #29686.