Uneven, Conchoidal, ConchoidalArthur Thomas, Gemstones (2009)
UnevenAnthony et al, Handbook of mineralogy (2001), UnevenAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Tourmaline is a series of several different minerals with unique chemical formulas. See The chemical formula of Tourmaline for details.
CaMoO 4Michael OâDonoghue , Gems, Sixth Edition (2006)