ConchoidalArthur Thomas, Gemstones (2009)
Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Metallic
MnTa 2O 6Walter Schumann , Gemstones of the world (2001) More from other references
Mg 2Si 2O 6Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references