Steel
Steel is the external physical pushing metal. A steel Misting is known as a Coinshot. A Coinshot burning iron can push bits of metal away from his center of gravity, and can also use steel to sense the presence of metal nearby. Steelpushing is not dependent on magnetic forces or Allomantic power--any metal can be pushed. Also, Steelpushing is dependent on weight. If a Coinshot pushes on something that weighs more then him (such as a coin) it will fly directly away from his center of gravity. But on the other hand, if he pushes on something heaver then himself (say a car, even though they don't have those in Mistborn) he will fly directly away from it. At the same time, if he stands over a coin laying on the ground and pushes on it he will fly straight up because the weight of the planet it transferred through the coin, adding to it's weight. Feruchemists can use iron to store physical speed, and when used as a Hemalurgic spike, steel steals the physical Allomantic powers (iron, steel, pewter and tin).