Bicolour tourmaline is a variety of tourmaline in which a single crystal naturally displays two distinct colors. This happens because the chemical composition of the crystal changes as it grows, causing different trace elements to be incorporated at different stages. Bicolour tourmaline Common color combinations include: * Pink and green (the most famous combination) * Blue and green * Pink and colorless * Yellow and green One especially well-known variety is: * Watermelon tourmaline, which resembles a slice of watermelon with a pink center and green edge…. From Afghanista Weight : 19 grams Average sizes : 17x4x4mm 24x4x2mm 17x3x2mm 14x4x4mm 18x3x2mm 15x5x5mm 14x4x4mm 10x3x3mm 15x4x3mm 14x2x2mm