Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
SrCO 3Walter Schumann , Gemstones of the world (2001) More from other references
(Fe,Mn) 7Si 7O 21Ulrich Henn and Claudio C.