UnevenArthur Thomas, Gemstones (2009) Tough, UnevenArthur Thomas, Gemstones (2009) Tough, Brittle, Uneven
Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Brittle, Uneven
Mn 8Si 6O 15(OH,Cl) 10Ulrich Henn and Claudio C.
ThCa 2Si 8O 20Walter Schumann , Gemstones of the world (2001) More from other references