Neon is important because it is used for lighting, signs, lasers and refrigeration. Neon is the fifth-most abundant element in the universe, but is very rare on Earth. Because it is rare and completely inert, it plays no known role in natural systems or biology.
Neon gives off a red-orange glow in a vacuum tube, which is used in lighting. Neon lights are named after the neon gas that gives them their color. Helium-neon lasers also get their red color from neon gas. This is the most common industrial use of neon.
Because it is a more efficient refrigerant than hydrogen or helium, neon is used in some cryogenic refrigeration applications. It is 40 times more efficient than helium and three times more efficient than hydrogen. While it is more expensive to isolate than hydrogen or helium, this efficiency makes it a cost-effective refrigerant.
Neon is rare on Earth due to its low weight, high vapor pressure and inability to form compounds with other elements. These factors prevent it from being trapped in Earth's atmosphere. Neon is slightly heavier than helium, but lighter than the other atmospheric gases; a neon-filled balloon rises in the air, though at a slower rate than a helium balloon.