ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Granular
NaAl 3(PO 4) 2(OH) 4 · 2H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Ca 2(Mg,Fe)Al 2(SiO 4)(Si 2O 7)(OH) 2 · H 2O)Arthur Thomas , Gemstones (2009)