Tungsten, a solid at room temperature, has an atomic weight of 183.84 and density of 19.3 grams per cubic centimeter. It melts at around 3410 degrees Celsius and boils at 5660 degrees Celsius. This transition metal and its alloys are used to manufacture filaments for electric bulbs and television tubes. It is also used for glass or metal seals because of its thermal expansion properties. Its sources include wolframite, ferberite and scheelite.