UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Conchoidal, ConchoidalAnthony et al, Conchoidal, Brittle, Conchoidal
Ca 2Mg 5Si 8O 22(OH) 2Ulrich Henn and Claudio C.
(Zn,Cu)Al 6(PO 4) 4(OH) 8 · 4H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)