Conchoidal, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle
Uneven, ConchoidalArthur Thomas, Brittle, Metallic
KNa 2Li(Fe2+ ,Mn2+ ) 2Ti 2Si 8O 24Michael OâDonoghue , Gems, Sixth Edition (2006)
Pb 5(PO 4) 3ClArthur Thomas , Gemstones (2009)