1) Mineral 2) Nickel mineral 
Smaltite is a variety of the mineral skutterudite consisting of cobalt iron nickel arsenide: (Co,Fe,Ni)As2. Smaltite crystallizes in the cubic system with the same hemihedral symmetry as pyrite; crystals have usually the form of cubes or cubo-octahedra, but are imperfectly developed and of somewhat rare occurrence. More often the mineral is found ...
• (n.) A tin-white or gray mineral of metallic luster. It is an arsenide of cobalt, nickel, and iron. Called also speiskobalt.
a cobalt-rich, arsenic-poor member of a series of cobalt nickel arsenide minerals (see skutterudite).[1 related articles]
[n] - a gray mineral consisting of cobalt arsenide and nickel
noun a grey mineral consisting of cobalt arsenide and nickel; an important source of cobalt and nickel