skutterudite

{{infobox mineral | name = Skutterudite | category = Arsenide mineral | boxwidth = | boxbgcolor = | image = Skuttérudite.jpg | imagesize = | alt = | caption = Skutterudite from Bou Azzer, Morocco | formula = CoAs3 | IMAsymbol = Skt | molweight = | strunz = 2.EC.05 | dana = | system = Cubic | class = Diploidal (m) H-M symbol: (2/m ) | symmetry = Im | unit cell = a = 8.204 Å, Z = 8 | color = Tin-white to silver-gray, tarnishes gray or iridescent; in polished section, gray, creamy or golden white | colour = | habit = Crystals are cubes, octahedra, dodecahedra, rarely prismatic; in skeletal growth forms, distorted aggregates; also massive, granular | twinning = On {112} as sixlings and complex shapes | cleavage = Distinct on {001} and {111}; in traces on {011} | fracture = Conchoidal to uneven | tenacity = | mohs = 5.5–6 | luster = Metallic | streak = Black | diaphaneity = Opaque | gravity = 6.5 | fluorescence= | absorption = | melt = | fusibility = | diagnostic = | solubility = | other = | alteration = | references = }} Skutterudite is a cobalt arsenide mineral containing variable amounts of nickel and iron 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 ore mineral found in moderate to high temperature veins with other Ni-Co minerals. Associated minerals are arsenopyrite, native silver, erythrite, annabergite, nickeline, cobaltite, silver sulfosalts, native bismuth, calcite, siderite, barite and quartz. 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.