ConchoidalWalter Schumann, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Metallic
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Perfect on {010}, good on {100}
Distinct on {100} and {110}
Be 2BO 3(OH)Ulrich Henn and Claudio C.
3NaAlSi 3O 8 · NaClAnthony et al , Handbook of mineralogy (2001)