Tanzanite & Diamond Cocktail Ring 14kt Two Tone Gold. Up for sale is a gorgeous ladies cocktail ring set with tanzanite and diamonds in 14kt two tone gold. The ring is set with a pear shaped tanzanite, medium blue in color, weighing approximately (0.22ct) and twenty-five round cut diamonds (0.25cttw). The ring is in very good condition with the ring size: 7. It is hallmarked: 14k and includes an insurance appraisal of $878.00.