ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Conchoidal, Brittle, Conchoidal, Brittle, Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
(Ca,Cr)MgSi 2O 6Gemdat.org , Management Team (2012)
PbSO 4Michael OâDonoghue , Gems, Sixth edition (2006) More from other references