Grey, Brown, Green, Colorless, White
White, Colorless, Blue, Red, Green, Yellow, Violet
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
ConchoidalArthur Thomas, Gemstones (2009)
Ca 2Mg 5Si 8O 22(OH) 2Ulrich Henn and Claudio C.
Tourmaline is a series of several different minerals with unique chemical formulas.