Yellow, Brown, Red, White, Green, Reddish, Black
Colorless, White, Brownish, Reddish, Black, Brownish, Black, Colorless, gray, White, Reddish, Brown
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Uneven
Uneven
Zn 2SiO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Na 3AlF 6Ulrich Henn and Claudio C.