UnevenArthur Thomas, Gemstones (2009) Tough, UnevenArthur Thomas, Gemstones (2009) Tough, Brittle, Uneven
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
Mn 8Si 6O 15(OH,Cl) 10Ulrich Henn and Claudio C.
(Fe,Mn) 7Si 7O 21Ulrich Henn and Claudio C.