Colorless, White, gray, Brownish, Greenish
Colorless, White, Brownish, Reddish, Black, Brownish, Black, Colorless, gray, White, Reddish, Brown
KAl 2AlSi 3O 10(OH) 2Walter Schumann , Gemstones of the world (2001) More from other references
Na 3AlF 6Ulrich Henn and Claudio C.