ConchoidalGemdat.org, Management Team (2012), ConchoidalGemdat.org, Management Team (2012)
Gems, Sixth Edition (2006), Gems, Sixth Edition (2006)
(Fe,Mg) 3Al 2(SiO 4) 3gemdat.org , Management Team (2012)
SiO 2Michael OâDonoghue , Gems, Sixth Edition (2006)