Pure blue tourmalines are much coveted on account of their beauty and rarity. In fine qualities, blue tourmalines are almost always one-offs. They are also highly esteemed by collectors. They are at their most valuable when they show an intense, clear, radiant blue which is not too dark, the kind of blue that puts one in mind of an aquamarine or a beautiful sapphire. The pure blue of the tourmaline radiates harmony. Perhaps it is for that reason that the gemstone therapists claim that a blue tourmaline makes people both honest and tolerant.