5.50 Carat Amethyst And .40 Ct. T.W. Tanzanite Ring In Sterling Silver 5.50 Carat Amethyst And .40 Ct. T.W. Tanzanite Ring In Sterling Silver. Size 7 Sizable This Ring Is All About Royal Hues. A 5.50 Carat Cushion-Cut Amethyst Is Centered Between Clusters Of Tanzanite Rounds Totaling .40 Carats. Black Rhodium. Set In Sterling Silver. 1/2" Wide. Tanzanite And Amethyst Ring