Handbook of mineralogy (2001), Difficult, Fibrous
Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001)
Ca 6Si 6O 17(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006)
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.