Swiss Blue Topaz Stud Earrings These stud earrings are handmade of 5 mm diameter Swiss Blue Topaz faceted stones in a 925 Sterling Silver low profile 4 prong setting. Two types of 925 Sterling backs are included for preference or just to have a backup pair (Rubber core bullet style and traditional friction catch). Polishing cloth included. Shipped in gift box. Blue Topaz is the Birthstone for November.