Tourmaline is a crystalline silicate mineral group in which boron is compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. It come in a wide variety of colors. It has a refractive index of 1.616 – 1.65 and a hardness of 7 – 7.5 on the Mohs scale. This beautiful piece of Tourmaline weighs 5.98 cts and measures 11x8x7mm and is eye clean.