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