You are viewing a very fine quality 18K yellow gold ring. The ring measures 17mm or 5/8" wide by 23mm. Set in the center is a fine quality 1 carat Tanzanite. Set in channels above and below the Tanzanite are fine quality Diamonds weighing around 1/2 carat in total. The sides of the ring are inlaid with bands of Black Opal. The ring is marked: 18K. It is a size 8 with a thick shank and can be re-sized. The ring weighs 12.2 grams.