Mishmetal
Although not a rare-earth element mishmetal is an alloy of rare earth elements in various naturally occurring proportions. It is also called cerium mischmetal, rare earth mischmetal or misch metal. A typical composition includes approximately 65% cerium and 35% lanthanum, with small amounts of neodymium and praseodymium. Its most common use is in the “flint” ignition device of many lighters and torches, although an alloy of only rare-earth elements would be too soft to give good sparks. For this purpose, it is blended with iron oxide and magnesium oxide to form a harder material known as ferrocerium.