ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Uneven, Uneven, Gems, Sixth Edition (2006), Uneven, Conchoidal
Ca 3Al 2(SiO 4) 3Arthur Thomas , Gemstones (2009)
NaAlSi 3O 8Michael OâDonoghue , Gems, Sixth Edition (2006)