Irregular/uneven, UnevenArthur Thomas, Gemstones (2009)
Splintery, Granular, Splintery, Granular, Gemstones (2009)
CaAl 2Si 4O 12 -6H 2OArthur Thomas , Gemstones (2009)
Ca 2(Mg,Fe) 5(OH) 2Walter Schumann , Gemstones of the world (2001) More from other references