Lanthanum's atomic number is 57 and its symbol is La. Lanthanum is a soft silvery-white rare earth metal that tarnishes in the atmosphere. It gets its name from an ancient Greek word meaning “to lie hidden” because it often occurs among other rare earth elements. Despite its early evasion from discovery, lanthanum is the 28th most abundant element in the earth's crust. It is mostly found in a variety of minerals such as monazite and bastnäsite.

Perhaps the most familiar use of lanthanum is in gas lantern mantles such as the mesh-like-bulbs in “Coleman” lanterns. It is also used to make glass, catalysts, cathodes, sparking farro rods, or welding electrodes.

The lanthanum sample in this element cube display is housed in an argon-filled glass ampule to prevent it from tarnishing over time.