Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001)
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Mg 2Al 4Si 5O 18Ulrich Henn and Claudio C.
Na 2Ca 2(CO 3) 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references