Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009)
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
(Fe,Mn)Ta 2O 6Walter Schumann , Gemstones of the world (2001) More from other references
ZrO 2Arthur Thomas , Gemstones (2009)