Colorless, Yellow, Brown, Green, Colorless, Green, Yellow, Red, Reddish, Brown
Green, Green, Yellow, Brown, White, gray, Black
Brittle, Metallic, Brittle, Metallic
Splintery, Granular, Splintery, Granular, Gemstones (2009)
Ca(Mg,Al)3(Al3Si)O10(OH)2
Ca 2(Mg,Fe) 5(OH) 2Walter Schumann , Gemstones of the world (2001) More from other references