To remove undesired hues, different heat treatment techniques as well as irradiation techniques are assumedly used on most rubellites available in the market. Some of these techniques, such as the heat treatment at low temperatures, are rarely identifiable by gem labs.
The rubellite grows in a hexagonal prism and is known, as most tourmalines, for its good clarity. Sharing the same crystal structure as the other coloured tourmalines, the rubellite’s complex molecular composition consists of Na(Li,Al)3Al6B3Si6O27 (OH)3(OH,F) with additional traces of manganese, which is responsible for its red or pink colour.
Tourmalines come in a wide range of colour. The variety rubellite comes in a pink to red colour range with purplish to orangish hues. The Gübelin Gem Lab defines a rubellite only if it comes in pink to red colour without the appearance of other secondary hues.
The finest rubellites come in strongly saturated red hues, making them more coveted by connoisseurs than pink rubellites or less saturated specimens.
Today’s major rubellite deposits, known for their fine red colour, are located in Brazil, Nigeria and Mozambique. More historical sources encompass mines in the Himalaya region, the United States, Afghanistan, Pakistan, Russia, Madagascar and Nigeria.