Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Brittle, Uneven
Conchoidal, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Metallic
ThCa 2Si 8O 20Walter Schumann , Gemstones of the world (2001) More from other references
PbCa 3Zn 4(SiO 4) 4Anthony et al , Handbook of mineralogy (2001)