White, Colorless, gray, pink
Colorless, Reddish, White, pink, Green, Yellow, Violet, White, pink, Green, Yellow, Violet, White, Colorless, Blue, Green, Brown, Yellow, pink, Violet, White, pink, Green, Yellow, Violet
Handbook of mineralogy (2001), Difficult, Fibrous
Uneven, UnevenArthur Thomas, Gemstones (2009)
Ca 6Si 6O 17(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006)
KCa 4Si 8O 20(F,OH) · 8H 2OUlrich Henn and Claudio C.