Uneven, Uneven, Gemstones of the world (2001) More from other references
Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
H 4Mg 3Si 2O 9Walter Schumann , Gemstones of the world (2001) More from other references
CaBePO 4(F,OH)Ulrich Henn and Claudio C.