ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle
ZrO 2Arthur Thomas , Gemstones (2009)
(Be,Cs) 3Al 2Si 6O 18 · 0.5H 2OUlrich Henn and Claudio C.