Uneven, Uneven, Gems, Sixth Edition (2006)
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
(Na,K)AlSi 3O 8Michael OâDonoghue , Gems, Sixth Edition (2006)
ZrO 2Arthur Thomas , Gemstones (2009)