Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle
Pb 5(AsO 4) 3ClMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Ca 9(Mg,Fe2+ )(PO 4) 6(PO 3OH)Anthony et al , Handbook of mineralogy (2001)