Brittle, Uneven
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Uneven
Mn2+5(PO 4) 2(PO 3OH) 2 · 4H 2O)Michael OâDonoghue , Gems, Sixth Edition (2006)
(Mn2+ ,Fe2+ ,Mg,Ca) 2(PO 4)(F,OH)Michael OâDonoghue , Gems, Sixth Edition (2006)