cerium
noun/ˈsɪəɹiəm/
Etymology From Ceres (“a famous asteroid”) + -ium. The element was discovered and named in 1803. It was named after the asteroid, which had been discovered recently (1801) and had been named after Ceres, the Roman goddess of agriculture. This was during an era when asteroids were culturally exciting things that humans were just beginning to understand properly in astronomical terms, and the era also featured a fascination with neoclassical themes and thus naming things after icons of ancient Greek and Roman mythology and literature.
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Usually A chemical element (symbol Ce) with an atomic number of 58, a very soft, ductile, silvery-white metal that tarnishes when exposed to air.
- Despite their name, rare earths are not so rare. The most common, cerium, is as plentiful in the Earth's crust as copper or lead. The difference between them and more familiar materials is that, in nature, rare earths are almost never found on their own. Rather, they're mixed with other minerals, and often at low concentrations, making them difficult to mine economically.2025 July 18, Timothy McLaughlin, “A Rebel Army Is Building a Rare-Earth Empire on China's Border. The Kachin Independence Organization fought for decades in obscurity. Now it's supplying essential minerals to manufacturers around the world”, in Bloomberg Businessweek, archived from the original on 18 Jul 2025:
- Derived terms
- cerate, ceriation, ceric, ceriferous, cerine, cerite, cerium dioxide, cerium metals, cerium oxide, cerium trichloride, ceroan, cerous, dicerium, ferrocerium, noncerium, organocerium, radiocerium, tricerium
- Related terms
- Ceres, ceria, allanite, bastnasite, CAN, hydroxylbastnasite, jeweler's rouge, jeweller's rouge, monazite, orthite, rhabdophane, synchysite