Conchoidal, Brittle
Conchoidal, Metallic, UnevenArthur Thomas, Gemstones (2009), Brittle, Conchoidal
(Mn2+ ,Fe2+ ,Mg)(Fe3+ ,Mn3+ ) 2O 4Anthony et al , Handbook of mineralogy (2001)
Cu 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references