Uneven, UnevenArthur Thomas, Gemstones (2009)
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Mg 3Si 4O 10(OH) 2Ulrich Henn and Claudio C.
LiAl(PO 4)(OH,F)Walter Schumann , Gemstones of the world (2001) More from other references