Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
Brittle, Uneven
Pb 5(AsO 4) 3ClMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Mn2+5(PO 4) 2(PO 3OH) 2 · 4H 2O)Michael OâDonoghue , Gems, Sixth Edition (2006)