ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Uneven, Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Uneven, Subconchoidal, Brittle, Metallic, Brittle, Metallic
Be 3Al 2Si 6O 18Ulrich Henn and Claudio C.
Zn 2(AsO 4)(OH)Michael OâDonoghue , Gems, Sixth edition (2006)