ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Uneven
Uneven, Uneven, Gems, Sixth Edition (2006)
Good on {110}
2,1 basal ; 2,1 prismatic ; 3,1 pinacoidal
Mg 3Al 6(Si,Al,B) 5O 21(OH)Walter Schumann , Gemstones of the world (2001) More from other references
KAlSi3O8