Bicolor Tourmaline by GIA

Bicolor Tourmaline by GIA. What is tourmaline, and what accounts for tourmaline color variations In this video, learn about the science behind rough bicolored tourmaline crystals and how the tourmaline gemstone forms such unique color variations in just one crystal. View an example of a tourmaline crystal that varies from red to green and back to red. Watermelon, bicolor and multicolored zoning occurs when the trace elements change in concentration or composition during a