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