1920s diamond fancy solitaire engagement ring

1920s diamond fancy solitaire engagement ring in platinum. Centred with an estimated 0.40ct round Old European cut diamond in a raised square collet setting, set to top and bottom with four round old cut diamonds in grain settings and flanked by six round eight cut diamonds in grain settings, to a stylish angular solitaire with three-dimensional details, millefrain decoration and subtlety pierced gallery, the slightly raised shoulders smooth to a solid shank. Marked platinum and iridium, American.