White, Colorless, Blue, Red, Green, Yellow, Violet
Colorless, Blue, Violet, White, Brown, Colorless, Blue, Violet, White, rose, Brown, gray, Colorless, White, Violet, gray, Colorless, White, Violet, gray
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Conchoidal, Brittle, Conchoidal, UnevenArthur Thomas, Gemstones (2009), Brittle, Conchoidal
SiO 2 + H 2OUlrich Henn and Claudio C.
CaSO 4Michael OâDonoghue , Gems, Sixth edition (2006) More from other references