Irregular/uneven, UnevenAnthony et al, Handbook of mineralogy (2001), Brittle, Uneven
Subconchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Irregular
Perfect on {110} and {1 1 0}
{100} imperfect, {110} indistinct; partings on {111} or {011}
CaAl 2Si 3O 10 · 3H 2OUlrich Henn and Claudio C.
SnO 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references