Conchoidal, Brittle, Conchoidal, Brittle, Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Irregular/uneven, UnevenArthur Thomas, Gemstones (2009)
Fe 3Al 2(SiO 4) 3Arthur Thomas , Gemstones (2009)
CaAl 2Si 4O 12 -6H 2OArthur Thomas , Gemstones (2009)