Emerald and diamond coronet cluster ring by Boucheron Paris, French, circa 1960. A yellow gold and platinum ring set with one central square emerald-cut untreated Colombian emerald in a yellow gold claw setting with an approximate weight of 2.60 carats, encircled by an undulating single border of twenty eight rectangular baguette cut diamonds in claw settings with an approximate total weight of 1.50 carats, to a ballerina cluster, flanked by split shoulders, on a double knife edge shank, and…