Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001)
Conchoidal, Brittle, Conchoidal, Brittle, Conchoidal, Brittle
Mg 2Al 4Si 5O 18Ulrich Henn and Claudio C.
(Mg,Fe2+ ) 2(Mg,Fe2+ ) 5Si 8O 22(OH) 2Anthony et al , Handbook of mineralogy (2001)