.68 Art Deco Transitional Cut Diamond Engagement Ring. 68 Art Deco Transitional Cut Diamond Engagement Ring. This vintage Art Deco diamond engagement ring features a . 68 carat genuine natural diamond on a platinum band. The primary stone is a transitional cut diamond, a more progressive relative to the Old European cut technique. This stone has an old world feel while maintaining a modern brilliant sparkle. Accented by two(2) . 03 carat diamonds on both sides, this six prong, Art Deco engagement ring