Uneven, ConchoidalArthur Thomas, Brittle, Metallic
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
Pb 5(PO 4) 3ClArthur Thomas , Gemstones (2009)
Pb 5(AsO 4) 3ClMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references