It's Elemental

Cerium was discovered by Jöns Jacob Berzelius and Wilhelm von Hisinger, Swedish chemists, and independently by Martin Heinrich Klaproth, a German chemist, in 1803. Cerium is the most abundant of the rare earth elements and makes up about 0.0046% of the earth's crust. Today, cerium is primarily obtained through an ion exchange process from monazite sand ((Ce, La, Th, Nd, Y)PO₄), a material rich in rare earth elements.

Pure cerium will ignite if it is scratched with a sharp object, but can be safely used if combined with other materials. Cerium is one of the rare earth elements used to make carbon arc lights which are used in the motion picture industry for studio lighting and projector lights. Cerium is also a component of Misch metal, a material that is used to make flints for lighters. Cerium is also used as a catalyst to refine petroleum and as an alloying agent to make special metals.

Cerium oxide (Ce₂O₃ and CeO₂) is a component of the walls of self cleaning ovens and of incandescent lantern mantles. Cerium oxide is also used to polish glass surfaces. Ceric sulfate (Ce(So₄)₂) is used in some chemical analysis processes. Other cerium compounds are used to make some types of glass as well as to remove color from glass.