Halogen lamps are equipped with tungsten filaments. The electrodes in gas discharge lamps and vacuum tubes are also made of the metal tungsten. Why? Tungsten is tremendously heat-resistant. It is extracted from tungsten oxide, which is pulverized and heated in reduction furnaces. The atmosphere in those furnaces consists of hydrogen that bonds with the oxygen of the oxide powder, leaving pure tungsten and water vapor behind. The powdered metal is pressed under a protective atmosphere of argon and hydrogen and then heated to give it its final form. Specialists refer to this process as sintering. The downstream drawing process produces the wire for the tungsten filaments.