Tourmaline is a beautiful gemstone with mysterious properties. It has intrigued early philosophers since the time of Ancient Greece. Not only has it the broadest colour spectrum among crystalline gems. It also shows two interesting properties, piezoelectricity and pyroelectricity. Its structure can accommodate different atoms. As a result, there are many multi-colour crystals.
Tourmaline gems were not recognised as a separate species until 18th century. The red and green varieties were commonly mistaken with ruby and emerald before modern tests were introduced. Late Chinese Empress Cixi was especially fond of Rubellite gems and purchased great amount of them from Californian mines.
Nowadays we have great variety of colours mined across the globe. Tourmalines can sell form a couple of dollars a carat for common variety, to tens of thousands per carat for good quality, rare stones like Paraiba.