All Elfpetite glass beads are made with the highest quality glass, sourced from all over the world. All Elfpetite beads have a silver core with a 3.5 mm hole that fits also Pandora Essence. Our cores are marked with E925. This logo stands for Elfpetite and sterling silver 925. If you want to be sure if your bead is an original Elfpetite, you can check the logo in the core.