Vintage Oval Jadeite and Diamond Cocktail Ring

This is a vintage mid-century style cocktail ring featuring a large, oval cabochon-cut jadeite jade central stone. The jade exhibits a vibrant, translucent 'imperial' green hue with a smooth, high-polish finish, measuring approximately 15mm in length. The center stone is secured by four substantial gold prongs. Flanking the central jade on the shoulders are eight round brilliant-cut diamonds (four on each side), set in silver-toned or platinum-colored baskets to enhance their brilliance. The mounting is constructed from yellow gold, likely 14k or 18k, showcasing an ornate 'birch bark' or textured finish on the substantial shank. A notable feature is the hinged 'Finger Fit' or expandable mounting design, which allows the ring to open and close over a large knuckle for a secure fit. The condition shows moderate vintage wear, including surface scratches on the metal and some darkening or tarnish (patina) around the stone settings. There is a visible hallmark or maker's stamp on the interior shank, though it is not fully legible from the image. The craftsmanship suggests a bespoke or high-end commercial piece from the 1960s-1970s, characterized by the heavy gold construction and the specific technical hardware of the adjustable shank.