Conchoidal, ConchoidalAnthony et al, Conchoidal, Brittle, Conchoidal
Uneven, Uneven, Gemstones of the world (2001) More from other references
(Zn,Cu)Al 6(PO 4) 4(OH) 8 · 4H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)
Ca 10Mg 2Al 4(SiO 4) 5(Si 2O 7) 2(OH) 4Ulrich Henn and Claudio C.