Approx. 1". Simple, black tourmaline is one of the most powerful grounding, purification, and protection stones. This affirmation sums up black tourmaline nicely, "I banish negativity; I'm protected on all levels. "Tourmaline is believed to promote inspiration and happiness, reduce fear, and build self-confidence among its users. It's also used to balance yin-yang energies, as it's considered a physical bridge to the spiritual. Tourmaline comes in a variety of colors, the most common being black.