Tourmaline obsession! Tourmaline forms in all colors of the rainbow however fancy red/ purple and blue greens are some of the rarest and most valuable. Not only is it beautiful but also useful in technology. Tourmaline is very piezoelectric (similar to quartz crystals) which means that when a mechanical stress is applied it generates on minute electrical charge, this unique feature has many practical applications in industry such as being used in pressure sensitive gauges and sensors for testing