White, Blue, Yellow, Brown, Green, Brownish, Greenish, gray
White, Colorless, Blue, Red, Green, Yellow, Violet, pink
Gemstones (2009), Flexible Flexible fragments.
Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle
Al 2Si 4O 10(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
(Be,Cs) 3Al 2Si 6O 18 · 0.5H 2OUlrich Henn and Claudio C.