ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Uneven, ConchoidalArthur Thomas, Brittle, Metallic
NaAl 3(PO 4) 2(OH) 4 · 2H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Pb 5(PO 4) 3ClArthur Thomas , Gemstones (2009)