Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
Conchoidal, ConchoidalAnthony et al, Conchoidal, Brittle, Conchoidal
Al 6B 5O 15(F,OH) 3Ulrich Henn and Claudio C.
(Zn,Cu)Al 6(PO 4) 4(OH) 8 · 4H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)