Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Brittle, Uneven
UnevenAnthony et al, Handbook of mineralogy (2001) More from other references, UnevenAnthony et al, Handbook of mineralogy (2001) More from other references, Brittle, Metallic
ThCa 2Si 8O 20Walter Schumann , Gemstones of the world (2001) More from other references
CoAsSAnthony et al , Handbook of mineralogy (2001)