Ferrocerium rod is made from Iron, Magnesium and mostly of an alloy of rare earth metals called mischmetal, which contains cerium, lanthanum and a small amounts of neodymium and praseodymium. The origin of its easy sparking is cerium's low temperature pyrophoricity, it's ignition temperature occurring between (150 to 180 degrees celsius). Since smaller scrapings become better sparks, the mechanical properties of rare earth metals must be adjusted to give a usable material;

Ferrocerium rod is widely used in flint lighter, outdoor firestarter(fire starter), survival kits(flint & steel kit) in scouting and camping, and sparking entertainment, clockwork toys and strikers for welding torches.

Ferrocerium is also known as Auermetall after its inventor Baron Carl Auer von Welsbach, it is sold under such trade names as Blastmatch, FireSteel, and Metal-Match.

While ferrocerium-and-steel function in a similar way to flint-and-steel in fire starting, ferrocerium actually takes on the role that steel played in traditional methods. When small shavings of it are removed quickly enough, the heat generated by friction is enough to ignite those shavings. The sparks generated are in fact tiny pieces of burning metal. 

The required chemical composition:

    Mischmetal(rare earth metal) : abt. 75%
    Iron                                       abt.18.1-19.3%
    Magnesium                                   3-4%
    Rare earth metal distribution :
    Cerium                                   49-51%
    Lanthanum                              26-34%
    Neodymium                             0-10%
    Praseodymium                         4-7%
Pyrophoric  percentage :  98%min.
Hardness :   70-90 HV
Dimension :     8.0mm up to 30mm Diameter  x  5mm up to 1000mm Length.