Cerium metal is a rare-earths metal. Cerium metal is a solid and golden metal at normal pressure and temperature, it is a very hard metal. It easily oxidizes turning its surface in black. Cerium metal is the most frequent of the lanthanoids (rare-earths), most of it occurs mixed with the others of them. Often it is used as mischmetal, which contains a natural lanthanoid mixture and is cheaper than the separated lanthanoids. This typically consists of 50% cerium, 20% lanthanum and neodymium, 5% praseodymium and the other lanthanoids in fewer amounts as well as iron and other elements. Iron and cerium are the only elements, where by hard and fast friction sparks can be produced.