UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Ca 2Mg 5Si 8O 22(OH) 2Ulrich Henn and Claudio C.
ZrO 2Arthur Thomas , Gemstones (2009)