Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Metallic
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Mg 2Si 2O 6Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Na(Fe2+3)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012)