Subconchoidal, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references
Subconchoidal, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal, Brittle
Octahedral, perfect on {111}, parting on {011}
{0001} good, {10 1 0} parting