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ConchoidalArthur Thomas, Gemstones (2009)
(Ca,Ce) 4 Na(Na,Ca) 2 Ti(Si 2 O 7 ) 2 F 2 (O,F) 2 Michael O’Donoghue, Gems, Sixth Edition (2006)
(Mg,Zn)Al 2O 4Gemdat.org , Management Team (2012)