Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
(Mg,Fe2+ ) 7(SiO 4) 3(F,OH) 2Anthony et al , Handbook of mineralogy (2001)
Al 6B 5O 15(F,OH) 3Ulrich Henn and Claudio C.