Uneven, Uneven, Irregular, Management Team (2012), Conchoidal, Brittle
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Ca 3Al 2(SiO 4) 3-x(OH) 4x (x=0.2 to 1.5)Anthony et al , Handbook of mineralogy (2001)
Be 3Al 2Si 6O 18Ulrich Henn and Claudio C.