Uneven, Uneven, Gems, Sixth Edition (2006), Uneven, Conchoidal
Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Metallic
NaAlSi 3O 8Michael OâDonoghue , Gems, Sixth Edition (2006)
Mg 2Si 2O 6Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references