Fracture
Not Available
Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009)
Chemical Composition
Na 4(Al,Si) 12O 24Cl to Ca 4(Si,Al) 12O 24(CO 3,SO 4)Arthur Thomas , Gemstones (2009)
(Mg,Fe2+ )Al 2O 4Gemdat.org , Management Team (2012) More from other references