Colorless, Yellow, Blue, Reddish, Black, Reddish, Brown, Blue, gray, Black, Reddish, Brown, Blue, gray
Green, Black, White, Grey, Green, Black, White, Grey, Green, Black, gray, Black, Green, Black, gray, Black
Subconchoidal, Conchoidal, Brittle, ConchoidalArthur Thomas, Gemstones (2009)
Uneven, UnevenArthur Thomas, Gemstones (2009), Splintery
TiO 2Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
Ca 2(Mg,Fe) 5Si 8O 22(OH) 2Ulrich Henn and Claudio C.