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