ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
(Ca,Mg,Mn)SiO 3Gemdat.org , Management Team (2012)
BaSO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references