Blue Enamel Diamond Cocktail Ring in 18k Yellow GoldBlue Enamel Diamond Cocktail Ring in 18k Yellow Gold. This groovy Mid Century cocktail ring features . 15 carats of single cut diamonds in blue enamel and 18 karat yellow gold. The near colorless diamonds are channel set in yellow gold at the center of the ring. A thick blue enamel coating covers the front of the tapered 18K yellow gold band. This ring is expertly designed and colorful a timeless work of Mid Century art!