Named after Skuterudåsen, a hill in Modum , skutterudite is a cobalt containing variable amounts of nickel substituting for cobalt with the ideal formula CoAs3. Some references give the arsenic a variable formula subscript of 2-3. High nickel varieties are referred to as nickel-skutterudite, previously chloanthite. It is a hydrothermal mineral found in moderate to high temperature veins with other Ni-Co minerals. Associated minerals are arsenopyrite, annabergite, silver sulfosalts , siderite It is mined as an ore of cobalt and nickel with a by-product of arsenic.
The crystal structure of this mineral has been found to be exhibited by several compounds with important technological uses.
The mineral has a bright metallic luster, and is tin white or light steel gray in color with a black streak. The specific gravity is 6.5 and the hardness is 5.5–6. Its crystal structure with cube and octahedron forms similar to that of pyrite. The arsenic content gives a garlic odor when heated or crushed.
Skutterudite was discovered in Skuterud Mines, Modum , Buskerud Smaltite is an alternative name for the mineral. Notable occurrences include Cobalt, Ontario , and Franklin, New Jersey. The rare arsenide minerals are classified in Dana's sulfide mineral group, even though it contains no sulfur.