4mm Tourmaline Multi-CircleNatural 4mm Tourmaline Ore Crystal Necklace Select high quality natural tourmaline ore crystals, each bead is carefully selected to present a clear ice cream like texture and gorgeous rainbow colors. Tourmaline is extremely rare in nature and is known as the "rainbow among gems". Its unique color changes are pleasing to the eye. Don't choose clear ice cream colored tourmaline, which is fresh and soft, giving people a sense of tranquility and comfort.