1.02 Oval Cut Tourmaline & Diamond Ring in 14k Yellow Gold1. 02 Oval Cut Tourmaline Diamond Ring in 14k Yellow Gold. This modern engagement ring features a 1. 02 carat green tourmaline and . 08 carats of accent diamonds finished in 14 karat yellow gold. The center tourmaline has a dark forest green hue and is set in four prongs. The oval cut facets of the tourmaline complement the large size of the gem. Two (2) . 04 carat Round Brilliant cut diamonds flank the center stone, adding a sparkle to the deep color