The different shades of colour have been assigned different names in the trade. For example, deep red Tourmaline is named "Rubellite”, provided it shows the same fine ruby-red shade in daylight and in artificial light. Should the colour change when the source of light changes, the stone will be called a "Pink Tourmaline”. Blue Tourmalines are called "Indigolith”, "Dravite” is a golden-brown to dark brown Tourmaline, and black Tourmalines are known as "Schorl”.