Colorless, Yellow, Brown, Green, Colorless, Green, Yellow, Red, Reddish, Brown
White, Colorless, Blue, Red, Green, Yellow, Violet
Brittle, Metallic, Brittle, Metallic
Conchoidal, Conchoidal, Gemstones of the world (2001)
Ca(Mg,Al)3(Al3Si)O10(OH)2
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)