Irregular/uneven, UnevenAnthony et al, Handbook of mineralogy (2001), Brittle, Uneven
Uneven, Uneven, Gemstones of the world (2001) More from other references
CaAl 2Si 3O 10 · 3H 2OUlrich Henn and Claudio C.
H 4Mg 3Si 2O 9Walter Schumann , Gemstones of the world (2001) More from other references