Opal & Diamond Ring. 14K Yellow Gold Round Opal & Diamond Ring. This yellow gold ring makes a great addition to any jewelry collection and can be worn on many occasions. This ring is prong set with 18 round shape diamonds. The diamonds have a total carat weight of 0.25 carats. The diamonds are GHI color and SI-I1 clarity. There is 1 round shape opal gemstone on this ring. The gemstone is prong set and has a total carat weight of 1.05 carats. This ring is part of our gemstone collection of jewelry.