ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Uneven, Conchoidal, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle
Na(Li 1.5Al 1.5)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012) Formula given for elbaite.
FeS 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references