UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Uneven
(Fe,Mn) 7Si 7O 21Ulrich Henn and Claudio C.
Mg 6Cr 2(CO 3)(OH) 16 · 4H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references