1920s sapphire and diamond two stone plaque ring

1920s sapphire and diamond two stone plaque ring in platinum and 18kt white gold, centred with two vertically set round mixed cut sapphires in hexagonal collet settings, set to each corner and flanked by round old cut diamonds in claw settings with intricate pierced openwork, flanked by tri-split shoulders which smooth to solid shank. Estimated total sapphire weight 1.72cts.