Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Al 6B 5O 15(F,OH) 3Ulrich Henn and Claudio C.
Ca 2Mg 5Si 8O 22(OH) 2Ulrich Henn and Claudio C.