ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
SiO 2 + H 2OUlrich Henn and Claudio C.
TiO 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references