When was lithium first isolated?

Lithium was first isolated in 1817 by the Swedish chemist Johan August Arfwedson while working in Jöns Jacob Berzelius’s laboratory. Arfwedson identified the new element in the mineral petalite. The name lithium comes from the Greek lithos, meaning stone, because it was found in mineral material rather than plant or animal sources. Lithium later became important in batteries, psychiatry, and light metal alloys.