One of the most abundant of the rare earth metals. Symbol, Ce. The minerals monazite and bastnasite are presently its two most important sources. It is used in the manufacture of pyrophoric alloy. The oxide is a constituent of incandescent gas mantles and is emerging as a catalyst in self-cleaning ovens. The sulfate is used as an oxidizing agent in quantitative analysis. Other cerium compounds are used in the manufacture of glass, as a polishing agent, and in carbon-arc lighting, petroleum refining, and metallurgical and nuclear applications.