Conchoidal, Brittle, Conchoidal, Brittle, Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001)
none
2,1 basal ; 2,1 prismatic ; 3,1 pinacoidal
Fe 3Al 2(SiO 4) 3Arthur Thomas , Gemstones (2009)
Plagioclase Feldspar s: (Na,Ca)Al1-2Si3-2O8 Orthoclase Feldspar : KAlSi3O8