Uneven, Conchoidal to uneven, Brittle, Metallic, Uneven, ConchoidalWalter Schumann, Brittle, Metallic
Fibrous, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references
Distinct on {110}, imperfect on {010}, poor on {001}
Distinct on {100}, poor on {110}; parting on {001}