Conchoidal, Brittle, Metallic, Conchoidal, Handbook of mineralogy (2001)
Irregular/uneven, UnevenArthur Thomas, Gemstones (2009)
(Mg,Fe2+ ) 3Si 2O 5(OH) 4Anthony et al , Handbook of mineralogy (2001)
CaAl 2Si 4O 12 -6H 2OArthur Thomas , Gemstones (2009)