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