White, Colorless, Blue, Red, Green, Yellow, Violet
Blue, White, Grey, Yellow, Green, Colorless, Red, gray
ConchoidalArthur Thomas, Gemstones (2009)
Uneven, Conchoidal, Brittle
Tourmaline is a series of several different minerals with unique chemical formulas.
(Na,Ca)4-8Al6Si6(O,S)24(SO4,Cl)1-2