Colorless, White, Brownish, Reddish, Black, Brownish, Black, Colorless, gray, White, Reddish, Brown
Blue, Green, Greenish, Black
Na 3AlF 6Ulrich Henn and Claudio C.
ZnAl 2O 4Michael OâDonoghue , Gems, Sixth Edition (2006)
Gemmological Tables (2004) More from other references
Gemmological Tables (2004) More from other references