I call these crackle beads because if you look closely, you can see a crackled appearance on the inside of the bead. It really makes this bead look three dimensional. This is a glass bead. Every bracelet is handmade and must pass a 3 point quality test to ensure the highest quality. All metal components are lead, nickel, and cadmium free. To use essential oils or fragrance on your bracelet simply place a drop of oil on each lava bead. Let it absorb for 20 minutes. Dab off excess oil and roll the bracelet onto your wrist. Repeat every 24 hours or as needed.