Detailed Old Euro Diamond Filigree Engagement Ring Art Deco. This antique Art Deco solitaire engagement ring features a .23 carat Old European cut diamond finished in 18 karat white gold. To either side of the stone, a geometric pattern with two rows of milgrain detail transcending down the ring’s shoulders into a delicate 18k white gold shank. Glittering and well-designed, this ring will make your engagement something to remember.