Uneven, ConchoidalArthur Thomas, Brittle, Metallic
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Pb 5(PO 4) 3ClArthur Thomas , Gemstones (2009)
SrCO 3Walter Schumann , Gemstones of the world (2001) More from other references