1940s French three stone diamond tank ring in 18kt yellow gold

1940s French three stone diamond tank ring in platinum and 18kt yellow gold. Centrally set with an estimated 1.00ct square step cut diamond in a platinum rubover setting, set at angles to either side with two square step cut diamonds in platinum rubover settings, to a chunky, three-dimensional cocktail ring with step sections in relief and broad raised shoulders which taper to a solid shank. Esimated total diamond weight 1.50cts. Hallmarked 18kt gold and platinum, French import marks.