Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Brittle, Uneven
Subconchoidal, Conchoidal, Brittle, ConchoidalArthur Thomas, Gemstones (2009)
ThCa 2Si 8O 20Walter Schumann , Gemstones of the world (2001) More from other references
TiO 2Michael OâDonoghue , Gems, Sixth edition (2006) More from other references