Sub-Conchoidal, ConchoidalArthur Thomas, Conchoidal, Uneven
Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Metallic
(Fe,Mn)AlPO 4(OH) 2 -H 2OArthur Thomas , Gemstones (2009)
Mg 2Si 2O 6Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references