ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Be 3Al 2Si 6O 18Ulrich Henn and Claudio C.
ZrO 2Arthur Thomas , Gemstones (2009)