Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle
Conchoidal, ConchoidalAnthony et al, Conchoidal, Brittle, Conchoidal
(Be,Cs) 3Al 2Si 6O 18 · 0.5H 2OUlrich Henn and Claudio C.
(Zn,Cu)Al 6(PO 4) 4(OH) 8 · 4H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)