Subconchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Conchoidal
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Perfect on {001}, poor on {201} with 38.5° angle between the two
Distinct on {100} and {110}
LiAlSi 4O 10Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
3NaAlSi 3O 8 · NaClAnthony et al , Handbook of mineralogy (2001)