Tungsten, also known as wolfram, is a chemical element with the chemical symbol W and atomic number 74. Tungsten is as known the heaviest materials except gold of the nature resources, for the density of tungsten is 19.25  g•cm−3(near r.t.). For the same reason, tungsten related products, alloys, other elements doped and carbides have the special characteristics as pure tungsten, then it always named heavy stone.
  Tungsten is one of Nonferrous Metals, and also it is as molybdenum and rare earth which are Refractory Metals, in the modern industrial time, it is the most important Strategic Metals for IT industrial and military industrial.
  How is tungsten used? Tungsten alloys are good conductors of electricity, and used primarily to increase the toughness and strength of steel. The most common tungsten product, cemented tungsten carbide, is used to make grinding wheels and cutting or forming tools. Tungsten powder is used as a lead replacement in bullets. However, firing of a tungsten/nylon bullet introduces tungsten and other projectile related metals into the environment.