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)
Conchoidal, Brittle, Conchoidal, UnevenArthur Thomas, Gemstones (2009), Brittle, Conchoidal
SiO 2Ulrich Henn and Claudio C.
CaSO 4Michael OâDonoghue , Gems, Sixth edition (2006) More from other references