Not Available
Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Brittle, Uneven
Ca 2(Mg,Fe,Mn,Al) 2(SiO 4)(Si 2O 7)(OH) 2 · H 2OUlrich Henn and Claudio C.
ThCa 2Si 8O 20Walter Schumann , Gemstones of the world (2001) More from other references