Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Brittle, Uneven
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Uneven
ThCa 2Si 8O 20Walter Schumann , Gemstones of the world (2001) More from other references
FeS 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references