ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Gems, Sixth Edition (2006), Gems, Sixth Edition (2006)
CaZrBAl 9O 18Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
SiO 2Michael OâDonoghue , Gems, Sixth Edition (2006)