Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009)
Subconchoidal, Conchoidal, Brittle, ConchoidalArthur Thomas, Gemstones (2009)
(Mg,Fe2+ )Al 2O 4Gemdat.org , Management Team (2012) More from other references
TiO 2Michael OâDonoghue , Gems, Sixth edition (2006) More from other references