Vintage Black Tourmaline Knotted Bead Necklace from Inherited This. Measuring a perfect 20", this striking piece is cool to the touch and boasts a weight of 93g, featuring exquisite 10mm beads. Each bead is carefully knotted to ensure durability and showcase the natural beauty of black tourmaline. Ideal for a sophisticated look or as a meaningful heirloom, this necklace embodies our commitment to quality and heritage.