Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001)
(Ca,Na)(Mg,Fe,Al)Si 2O 6Anthony et al , Handbook of Mineralogy (2001)
Mg 2Al 4Si 5O 18Ulrich Henn and Claudio C.