Irregular/uneven, UnevenAnthony et al, Handbook of mineralogy (2001), Brittle, Uneven
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Uneven
CaAl 2Si 3O 10 · 3H 2OUlrich Henn and Claudio C.
Mg 6Cr 2(CO 3)(OH) 16 · 4H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references