ConchoidalWalter Schumann, Gemstones of the world (2001), ConchoidalWalter Schumann, Gemstones of the world (2001)
UnevenAnthony et al, Handbook of mineralogy (2001), UnevenAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
SiO 2Ulrich Henn and Claudio C.
CaMoO 4Michael OâDonoghue , Gems, Sixth Edition (2006)