Rubellite is the red variety of tourmaline, similar in colour to ruby from which the name is derived. The most valuable stones have a colour similar to that of a 'good quality ruby'. Higher priced stones have a colour that is fairly consistent when viewed in daylight and artificial light. Less valuable stones turn brownish when viewed in incandescent light (from a filament light bulb).
Inclusions are common in rubellite and seem to appear more in stones with a darker hue.
Major source locations for rubellite include: Africa (Nigeria), Afghanistan, Brazil, Madagascar and the USA (California)
Tourmalines may be heat-treated or irradiated to improve their colour. Treated stones are normally stable, but when subject to prolonged exposed to heat or strong light, they may fade.