Early 20th century opal and diamond brooch, c 1905, the central blue green opal in gold claw mount, to an old brilliant-cut diamond border, set in platinum, with trefoil detail at the cardinal points, gold pin fitting to the reverse
The OPAL collection of Princess Ceril Birabongse of Siam - Opal and diamond brooch, circa 1910 - The polished opal within an openwork border millegrain-set with circular-, single-cut and rose diamonds.
OPAL, RUBY AND DIAMOND BROOCH EARLY CENTURY Centring on an oval opal within a surround millegrain-set with circular-cut diamonds and variously shaped rubies, suspending a similarly set opal terminating on an opal drop, fitted case WM Bruford Son Ltd.
OPAL AND DIAMOND CLIP, France, ca. Decorative, geometrically open-worked clip brooch, the centre set with 1 oval black opal of ca. ct and set throughout with 107 single-cut diamonds weighing ca. Clip in white gold - by Koller Auctions