UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
Uneven, Uneven, Gemstones of the world (2001) More from other references
Ca 2Mg 5Si 8O 22(OH) 2Ulrich Henn and Claudio C.
Ca 10Mg 2Al 4(SiO 4) 5(Si 2O 7) 2(OH) 4Ulrich Henn and Claudio C.