Art Deco Ruby Engagement Ring in 18k White GoldArt Deco Ruby Engagement Ring in 18k White Gold. This engagement ring features a . 89 carat Round Brilliant cut, natural red ruby accented by old mine cut diamonds. Each of the . 10ct old mine cut diamonds are as beautiful as the center ruby and the polished 18k white gold band gives this engagement ring a mystic beauty. Born of the Art Deco period between 1915 1939, this lovely ruby engagement ring is an antique from another world.