Natural Black Obsidian 10mm Bead Necklace and Bracelet Set, with Black Nylon Macrame Knot Closure, Adjustable. This necklace and bracelet set features strands of all natural black obsidian beads, 10mm wide, woven on black nylon. The necklace is fully adjustable, from 22" to 25" with macramé knot closure. The matching bracelet is fully adjustable, from 7" to 10" with macramé knot closure. Comes with gift box and lifetime warranty.