ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Uneven, Irregular, Management Team (2012)
NaAl 3(PO 4) 2(OH) 4 · 2H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references
(Mg,Fe2+ ) 3Si 2O 5(OH) 4Anthony et al , Handbook of mineralogy (2001)