Blue Topaz CharmA 64mm oval blue topaz with a white CZ accent in a 13. 54mm 925 sterling silver setting the Blue Topaz is the clearest, coolest blue in the charm range. Blue topaz at this size has the specific sky blue quality that distinguishes it from aqua CZ or sapphire: lighter, more transparent, more atmosphere. At 0. 45g, the lightest stone charm in the range. The setting is slim and precise, letting the stone's colour and clarity carry the piece without any