Irregular/uneven, UnevenArthur Thomas, Gemstones (2009)
UnevenAnthony et al, Handbook of mineralogy (2001) More from other references, UnevenAnthony et al, Handbook of mineralogy (2001) More from other references, Brittle, Metallic
CaAl 2Si 4O 12 -6H 2OArthur Thomas , Gemstones (2009)
CoAsSAnthony et al , Handbook of mineralogy (2001)