Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Conchoidal, Conchoidal, Gemstones of the world (2001)
3NaAlSi 3O 8 · NaClAnthony et al , Handbook of mineralogy (2001)
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)