ConchoidalWalter Schumann, Gemstones of the world (2001), ConchoidalWalter Schumann, Gemstones of the world (2001)
Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Brittle, Uneven
CaTiSiO 5Ulrich Henn and Claudio C.
ThCa 2Si 8O 20Walter Schumann , Gemstones of the world (2001) More from other references