Uneven, Conchoidal, Brittle, Metallic, ConchoidalArthur Thomas, Gemstones (2009)
Uneven, UnevenAnthony et al, Handbook of mineralogy (2001)
Ca 3Cr 2(SiO 4) 3Ulrich Henn and Claudio C.
Pb 5Cu 2(SO 4) 3(CO 3)(OH) 6Anthony et al , Handbook of mineralogy (2001)