Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Brittle, Uneven
Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009)
ThCa 2Si 8O 20Walter Schumann , Gemstones of the world (2001) More from other references
(Fe,Mn)Ta 2O 6Walter Schumann , Gemstones of the world (2001) More from other references