Colorless, Yellow, Brown, Green, Red, Reddish
Yellow, Greenish, Brownish, Colorless, White, gray, Green, Blue, Violet, orange
Brittle, Metallic
Conchoidal, Brittle, ConchoidalArthur Thomas, Gemstones (2009)
Ca(Mg,Al)3(Al3Si)O10(OH)2
PbSO 4Michael OâDonoghue , Gems, Sixth edition (2006) More from other references