Tressa: 0.96ct Simulated Swiss-Blue Topaz Stackable Eternity Band Ring 925 Silver, 3294B Measuring only approx. 2.5mm in width, they are a great size for stacking multiples of them together. Made with Solid 925 Sterling Silver. Made with shimmering Simulated Swiss-Blue Topaz gemstones, the Tressa is the Simulated Swiss-Blue Topaz version from our Montana line.