ConchoidalAnthony et al, Handbook of mineralogy (2001), ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
ConchoidalWalter Schumann, Gemstones of the world (2001), ConchoidalWalter Schumann, Gemstones of the world (2001)
CaBe 2(PO 4) 2Michael OâDonoghue , Gems, Sixth Edition (2006)
SiO 2(+Al 2O 3)Walter Schumann , Gemstones of the world (2001)