Conchoidal, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
SiCArthur Thomas , Gemstones (2009)
SiO 2 + H 2OUlrich Henn and Claudio C.