2.47 Old European Cut Diamond Engagement Ring in Platinum2. 47 Old European Cut Diamond Engagement Ring in Platinum. This Art Deco beauty features a 2. 47 carat Old European cut diamonds that is set in platinum. The diamond is GIA certified and has tremendous quality, especially for an old cut stone. The center stone is set with fishtail prongs that are outlined with milgrain detail, giving the mounting a very clear square shape. On each shoulder sit three (3) beautiful marquise cut diamonds to add some