Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
SrCO 3Walter Schumann , Gemstones of the world (2001) More from other references
Al 6B 5O 15(F,OH) 3Ulrich Henn and Claudio C.