Uneven, Conchoidal, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle
Uneven, Uneven, Gems, Sixth Edition (2006)
Indistinct on {001}; partings on {011} and {111}
2,1 basal ; 2,1 prismatic ; 3,1 pinacoidal