ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Conchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Conchoidal, Brittle
Be 3Al 2Si 6O 18Ulrich Henn and Claudio C.
CuSiO 2(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references