UnevenAnthony et al, Handbook of mineralogy (2001) More from other references, UnevenAnthony et al, Handbook of mineralogy (2001) More from other references, Brittle, Metallic
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
CoAsSAnthony et al , Handbook of mineralogy (2001)
Be 3Al 2Si 6O 18Ulrich Henn and Claudio C.