Czech Glass Crystals Stud earrings are featuring 10mm spheres crafted of light-blue Ferido™ Formula x1, which is a moldable two-part epoxy adhesive used in jewelry creations, set with Czech Crystals, an abundant sparkle is achieved.. Set in Sterling Silver and with silver butterfly backs these Stud earrings display their rich glitter, embellishing a woman with a highly elegant silver crystal jewelry that displays a timeless beauty and latest fashion colors.