An opal and diamond brooch-pendant, circa 1905. Photo Bonhams The oval cabochon opal within a millegrain-set surround of single-cut diamonds, interspersed by three collet-set old brilliant-cut diamonds at each cardinal point, diamonds approximately 0.90...

25.69 carats oval cabochon opal and diamond ring The oval cabochon opal weighing 25.69 carats, framed by small round diamonds, the sides and band further decorated with small round diamonds, the total diamond weight approximately 1.80 carats, mounted...