Colorless, Blue, Violet, White, Brown, Colorless, Blue, Violet, White, rose, Brown, gray, Colorless, White, Violet, gray, Colorless, White, Violet, gray
Not Available
Conchoidal, Brittle, Conchoidal, UnevenArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Not Available
CaSO 4Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)