ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
ZrO 2Arthur Thomas , Gemstones (2009)
LiAl(PO 4)(OH,F)Walter Schumann , Gemstones of the world (2001) More from other references