Irregular/uneven, UnevenAnthony et al, Handbook of mineralogy (2001), Brittle, Uneven
Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle
CaAl 2Si 3O 10 · 3H 2OUlrich Henn and Claudio C.
(Be,Cs) 3Al 2Si 6O 18 · 0.5H 2OUlrich Henn and Claudio C.