18K 2.5 CT OPAL & DIAMOND PENDANT ON 18K CHAIN: 18K yellow gold pendant (tested) contains one cabochon cut semi-crystal opal. Orange bodycolor with blue/green pinfire play-of-color. WEIGHT: 3.40 Ct Approx. Brightness level: 3. One round brilliant cut diamond. WEIGHT: .06 Ct. Approx. Rated VS in clarity and G-H in color. 18K marked 18'' chain attached. Weight: 4.2 grams.