Conchoidal, Conchoidal, Gemstones of the world (2001)
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001) More from other references
Na 2Ca 2(CO 3) 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references