ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
ZrSiO 4Michael OâDonoghue , Gems, Sixth Edition (2006)
(Al,Mn3+ ) 2SiO 4OGemdat.org , Management Team (2012)