Lithium gets its name from the Greek word lithos, meaning “stone.”

Lithium is typically stored in oil to prevent it from reacting with air and corroding.

It’s often used in fireworks to produce a bright crimson-red color.

It is the least dense metal and the least dense solid element. Pure lithium is so soft that you can cut it with a knife. It can also float on water, but it reacts with it, so placing it in H₂O is not recommended.

Johan August Arfwedson discovered lithium in 1817, isolating it as a type of salt but not as pure lithium.

Despite being element number 3—and thus a relatively simple element—lithium is far less abundant in the solar system than many of the first 25 elements.

In 1932, scientists successfully turned lithium atoms into helium, marking the first man-made nuclear reaction.

Lithium is also a key ingredient in some medications used to treat mood disorders, including depression.