A heavy, hard metal with a high melting point that conducts electricity well, tungsten is used for a filament in tungsten halogen lamps.
Merriam-Webster Online Dictionary
tungsten (noun)a gray-white heavy high-melting ductile hard polyvalent metallic element that resembles chromium and molybdenum in many of its properties and is used especially in carbide materials and electrical components (as lamp filaments) and in hardening alloys (as steel) - see element table
tungsten, wolfram, heavy stone, element 74, W, scheelite
