Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
Handbook of mineralogy (2001)
Pb 5(AsO 4) 3ClMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references
(Ca,Mn2+ ) 2(SiO 3OH)(OH)Anthony et al , Handbook of Mineralogy (2001)