(also cloanthite), a zonal variety of minerals of the skutterudite group (Co, Ni) As_3±x, with a predominance of nickel. Some scientists use the term “chloanthite” to denote the pure nickel variety of skutterudite. Often there are admixtures of iron and sulfur. Chloanthite crystallizes in the isometric system, but crystals are rare. It occurs most often in the form of irregular grains or granular aggregates. The color ranges from tin white to steel gray. Chloanthite has a metallic luster, a hardness of 6 on Mohs’ scale, and a density of 6,400–6,800 kg/m³. A typical hydrothermal mineral of medium temperatures, it is a constituent of the ores of certain nickel-cobalt, silver-nickel-cobalt, and other deposits.