Retro 1940's Diamond Engagement Ring in 14kRetro 1940s Diamond Engagement Ring in 14k. This unique Retro engagement ring features a 1. 11 carat round brilliant cut diamond set in 14 karat white and yellow gold. The brilliant diamond is set with four (4) yellow gold prongs above . 09 carats of accent diamonds on the slightly raised shoulders. The shank is yellow gold, which provides pretty contrast with the white gold milgrain sections on the shoulders.