Conchoidal, Gems
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
NaAl 3(PO 4) 2(OH) 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
ZrSiO 4Michael OâDonoghue , Gems, Sixth Edition (2006)