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