Cerium (atomic number: 58) is the most abundant of the rare earth metals. Cerium is an iron-grey, lustrous, malleable metal. Except for europium, cerium is the most reactive of the rare-earth metals, and oxidises easily at room temperature

Discovered in 1803, it is named after the asteroid Ceres, the largest known asteroid in the traditional asteroid belt between the planets Mars and Jupiter.

Cerium oxide is used in the manufacture of glass, both as a component and as a decolorizer. Other uses of Cerium and Cerium compounds include the walls of self-cleaning ovens, carbon-arc lighting (used by the motion picture industry) and cigarette lighter flints .