Uneven, torn surfaces, (e.g. fractured metals)., Uneven, Gemstones (2009), torn surfaces, (e.g. fractured metals).
Conchoidal, Brittle
FeO(OH)Arthur Thomas , Gemstones (2009)
(Mn2+ ,Fe2+ ,Mg)(Fe3+ ,Mn3+ ) 2O 4Anthony et al , Handbook of mineralogy (2001)