White, Colorless, Blue, Red, Green, Yellow, Violet
Colorless, Yellow, Brown, Green, Colorless, Green, Yellow, Red, Reddish, Brown
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Brittle, Metallic, Brittle, Metallic
SiO 2 + H 2OUlrich Henn and Claudio C.
Ca(Mg,Al)3(Al3Si)O10(OH)2