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