Engagement Ring Modern .68 Old European Cut Diamond in Platinum. This modern platinum engagement ring was inspired by the style of the Art Deco era. In its center is a prong set Old European cut diamond. On either side of the diamond theres geometric shaped openwork that gives the rings design depth. The openwork is flanked by bead-set diamonds and all of it is surrounded in milgrain detail which was popular in rings made in the 1920s.