Antique Art Nouveau 18K White Gold & Platinum 3 Stone Diamond Engagement Ring. The ring is in excellent estate condition and ready to wear. Most of the ring is 18K white gold but the diamonds are set in platinum. The ring is set with three old European cut diamonds that come to approximately .79 carats total. The center stone is about .45 and it is flanked by a .18 carat and .16 carat diamond. The diamonds are Si2 - I1 clarity and J/K color. The ring is about a size 5.75 and weighs a total of 3.5 grams.