Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009)
Uneven, UnevenArthur Thomas, Gemstones (2009), Splintery
(Mg,Fe2+ )Al 2O 4Gemdat.org , Management Team (2012) More from other references
Ca 2(Mg,Fe) 5Si 8O 22(OH) 2Ulrich Henn and Claudio C.