ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Conchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001), Brittle
SiO 2 + H 2OUlrich Henn and Claudio C.
Be 2SiO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references