1) Nickel mineral 
Jolliffeite is a rare selenide mineral with formula NiAsSe or (Ni,Co)AsSe. It is the selenium analogue of the sulfide mineral gersdorffite, NiAsS, with a common impurity of cobalt, CoAsSe. It is named for its discoverer, Alfred Jolliffe, (1907–1988), a Canadian geologist of Queen`s University, Kingston, Ontario. ==Crystallography== Jolliffeite ....