White, Colorless, Blue, Red, Green, Yellow, Violet
White, Colorless, Blue, Red, Green, Yellow, Violet
ConchoidalArthur Thomas, Gemstones (2009)
Conchoidal, Conchoidal, Gemstones of the world (2001)
Tourmaline is a series of several different minerals with unique chemical formulas.
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)