Tank ring in 750 thousandths pink gold and 850 thousandths platinum, centered on an old cushion-cut diamond weighing approx. 1.40 ct and shouldered by ten old brilliant-cut diamonds. French work, 1940s. M. O. : Charles FONTANA (active from 1882 to 1962). Diamond size : 7.9 x 6.5 x 4 mm Total estimated diamond weight : 1.80 ct Finger : 53 - Gross weight : 11 g