Retro Cabochon Opal Cocktail Ring in 14KRetro Cabochon Opal Cocktail Ring in 14K. This enchanting cocktail ring comes to us from the Retro Era and features amazing engravings in 14 karat yellow gold and a . 57 carat cabochon cut opal. The opal is rather tall, which enhances the depth of color, and is set in a gorgeously engraved hexagon section. The intricate engravings continue down each side of the shoulders and speak to the level of care and craftsmanship in many Victorian jewelry works.