Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Brittle, Metallic
LiAl(PO 4)(OH,F)Walter Schumann , Gemstones of the world (2001) More from other references
CuSMichael OâDonoghue , Gems, Sixth edition (2006) More from other references