Cerium

rare-earth metal · chemistry · lanthanides

Silvery and soft. Cerium is a shiny, soft metal that looks like silver but tarnishes quickly when it touches air, turning its surface dull and darker.

Two stable forms. Most rare-earth metals stick to one electrical form, but cerium can be +3 or +4 and stays stable in both. The +4 form is extra special because it doesn't react with water like other metals do.

Second in the series. Cerium is the second element in the lanthanide family, a group of metals that are often found mixed together in nature and called rare-earth elements.

Not very toxic. Unlike some heavy metals, cerium doesn't poison your body easily. It only becomes dangerous if you're exposed to huge amounts over a long time.