Subconchoidal, Conchoidal, Brittle, ConchoidalArthur Thomas, Gemstones (2009)
ConchoidalGemdat.org, Management Team (2012), ConchoidalGemdat.org, Management Team (2012)
TiO 2Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
(Fe,Mg) 3Al 2(SiO 4) 3gemdat.org , Management Team (2012)