Colorless, White, Brownish, Reddish, Black, Brownish, Black, Colorless, gray, White, Reddish, Brown
White, White, Colorless, Red, Reddish
Uneven
Uneven, Brittle, Metallic, Gemstones (2009)
Na 3AlF 6Ulrich Henn and Claudio C.
Na 2[Al 2Si 3O 10] · 2H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references