Irregular/uneven, UnevenAnthony et al, Handbook of mineralogy (2001), Brittle, Uneven
Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Perfect on {110} and {1 1 0}
Poor on {120}, in traces on {001}
CaAl 2Si 3O 10 · 3H 2OUlrich Henn and Claudio C.
TiO 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references