New Diffuser Necklace - 45cm length - Stainless Streel Square/Diamond Bead with Lava Stone Bead captive within Lead Free, Nickel Free, Cadmium Free Lava Stones are porous and can absorb the essential oil of your choice. Add a drop or two of the oil to the black lava stone and the scent will last a day or more. Bundle and save! 2/$20