Tourmaline is one of the most interesting stones available on the gemstone market today. It can be found in almost any color imaginable but is rarely colorless. The complex chemical structure that creates tourmaline is what also generates its unique colors. The slightest change in composition makes this mineral change colors. Tourmaline can also be found with multi-colored crystals. They can be different colors from end to end or with a different color on the inside of the crystal than on the outside. These unique characteristics and its easy availability make Tourmaline a very popular and affordable gemstone.