Colorless, White, Yellow, White, Greenish, gray, Brown, Colorless, Yellow
White, Colorless, Blue, Red, Green, Yellow, Violet
Conchoidal, Brittle, Conchoidal
ConchoidalArthur Thomas, Gemstones (2009)
AlO(OH)Walter Schumann , Gemstones of the world (2001) More from other references
Tourmaline is a series of several different minerals with unique chemical formulas.