Colorless, Greenish, Colorless, Green, gray, Yellow
Colorless, Yellow, Blue, Reddish, Black, Reddish, Brown, Blue, gray, Black, Reddish, Brown, Blue, gray
Irregular/uneven, Uneven
Subconchoidal, Conchoidal, Brittle, ConchoidalArthur Thomas, Gemstones (2009)
Ca 2Al 3(SiO 4) 3(OH)Walter Schumann , Gemstones of the world (2001) More from other references
TiO 2Michael OâDonoghue , Gems, Sixth edition (2006) More from other references