Conchoidal, Brittle, Conchoidal, Brittle, Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Sub-Conchoidal, ConchoidalArthur Thomas, Conchoidal, Uneven
PbSO 4Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
(Fe,Mn)AlPO 4(OH) 2 -H 2OArthur Thomas , Gemstones (2009)