White, Colorless, Blue, Red, Green, Yellow, Violet
Grey, Brown, Green, Colorless, White
Not Available
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
SiO 2 (with trace Cr minerals) Gemdat.org , Management Team (2012)
Ca 2Mg 5Si 8O 22(OH) 2Ulrich Henn and Claudio C.