Uneven, Subconchoidal, Uneven, Subconchoidal, Splintery, UnevenArthur Thomas, Gemstones (2009)
ConchoidalArthur Thomas, Gemstones (2009)
Al 2SiO 5Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
MnTa 2O 6Walter Schumann , Gemstones of the world (2001) More from other references