Conchoidal, Brittle, Conchoidal, Brittle, Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Fe 3Al 2(SiO 4) 3Arthur Thomas , Gemstones (2009)
CaBePO 4(F,OH)Ulrich Henn and Claudio C.