Tourmaline gemstones can be found in all colours of the rainbow. Owing to its wide range of colour availability, tourmaline is considered to be one of today's most versatile gemstones. Its name is thought to be derived from the Sinhalese word, "turamali", which means "stone with various colours" in reference to its extreme versatility.
Since tourmaline consists of a very large group of related gemstones, most tourmaline is traded under very colour-specific varietal names. Some of the more popular trade names include pink-red 'rubellite', blue-green 'paraiba', blue 'indicolite' and multicoloured 'watermelon tourmaline'. Lesser-known trade names include colourless 'achroite', green 'verdelite' and 'chrome tourmaline'. Like sapphire, descriptive names such as 'yellow tourmaline' or 'pink tourmaline' are also commonly used to market fancy-coloured tourmaline gemstones.
Most tourmaline is completely untreated. However, some stones may be heated to improve colour and clarity. Yellow, pink and red varieties of tourmaline may be irradiated to enhance colour, although irradiation is nearly impossible to detect and does not normally affect value. Heavily included rubellite and paraiba tourmaline may be clarity enhanced.