The element lithium burns in a flame test as a vivid crimson red. Generally, flame tests are conducted to identify metal ions in a compound. Lithium is typically present in the solid compound lithium carbonate when tested in such a manner.
The lightest of the metals, lithium was first discovered in the mineral petalite in 1817 by Johann August Arfvedson. The element is not naturally found by itself, and is generally scarce; it makes up less than 0.0007 percent of the Earth's crust. It is used in a variety of industrial compounds, and is taken by humans in the form of lithium carbonate as a treatment for depression.