Uneven, Conchoidal, UnevenArthur Thomas, Brittle
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Fe2+ CO 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
(Ca,Mg,Mn)SiO 3Gemdat.org , Management Team (2012)