Multicolor tourmaline can't be said to be discolored. The real color-changing tourmaline means that its body color changes with the energy distribution or wavelength of the light source. Simply put, a gem shows one color under incandescent lamp or candlelight and another color under fluorescent lamp or sunlight. However, the discolored tourmaline is very rare, very rare. As for why it changes color, there is no specific information about what elements cause it to change color, which may be related to chromium and vanadium.