Irregular/uneven, UnevenAnthony et al, Handbook of mineralogy (2001), Brittle, Uneven
Gems, Conchoidal, Brittle
CaAl 2Si 3O 10 · 3H 2OUlrich Henn and Claudio C.
Ca 3Ti4+2(Fe3+2Si)O 12Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references