Like all metals, tungsten is ductile and malleable, and conducts heat as well as electricity. For these reasons, tungsten is an ideal candidate for an incandescent light bulb's filament.
Of all metals found on the periodic table, tungsten has the highest melting point at 3,410 degrees Celsius. Because a filament will need to heat up to several thousand degrees to produce consistent light, using tungsten in the construction of filaments is the industry norm.
Tungsten occurs naturally in a few materials, such as wolframite. China produces nearly 75 percent of the world's supply of tungsten.
Of all known metals, tungsten has the highest tensile strength. It is a dense material but can be very brittle. Despite its high melting point, tungsten filaments slowly evaporate and snap or melt, which is why incandescent light bulbs do not last very long.
Halogen light bulbs are incandescents with traces of a halogen in their fill gas. The halogen acts to preserve the tungsten filament by redepositing evaporated tungsten back onto the filament.