Conchoidal, ConchoidalAnthony et al, Conchoidal, Brittle, Conchoidal
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Uneven
(Zn,Cu)Al 6(PO 4) 4(OH) 8 · 4H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)
FeS 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references