Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Metallic
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Mg 2Si 2O 6Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
LiAl(PO 4)(OH,F)Walter Schumann , Gemstones of the world (2001) More from other references