Centering a Round Brilliant cut diamond weighing app. 1.35ct. (FG SI2), in a four prong mount, set with and flanked by Old European cut diamonds, all weighing app. 0.42ctw., fashioned in platinum. Partially obscured (from wear) Tiffany & Co mark. Center diamond is a later replacement. Circa 1915. Size 6.25EGL US69193501