UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Fibrous, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references
Perfect on {110} at 56° and 124°; partings on {010} and {100}
Distinct on {100}, poor on {110}; parting on {001}