ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Subconchoidal, Uneven, Conchoidal, Uneven
MgAlBO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Mn2+ Al(PO 4)(OH) 2H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)