Mischmetal is an alloy produced from electrolysis of mixed rare-earth metals, with the exact composition depending on the origin of the source material. The majority of mischmetal consists of lanthanum and cerium, with smaller amounts of praseodymium, neodymium, and samarium. All of the other stable rare earths are present in some quantity. It is extremely prone to corrosion, and sparks dramatically when struck, throwing out globs of molten metal.
When alloyed with iron and some added metal oxides the harder alloy ferrocerium is formed, which is commonly used in "flints."