An anvil is a metalworking tool that is used to shape metal by striking it with a hammer. It consists of a large block of metal, usually forged or cast steel, with a flattened top surface. The top surface is called the face, and it is made of hardened steel. Anvils are as massive as practical, because the higher their inertia, the more efficiently they cause the energy of striking tools to be transferred to the workpiece. The blacksmiths anvil is usually of wrought iron, but sometimes of cast iron, with a smooth working surface of hardened steel. A projecting conical beak, or horn, at one end is used for hammering curved pieces of metal, while the other end may have a beak with a rectangular section. There are many minor and major variations of anvil design depending upon where in the world the anvil hails from. Some anvils have different shapes, such as protrusions on their sides or with a horn at each end, which are designed for a specific task such as shoeing horses. The different parts of an anvil include the horn, face, step, hardy hole, pritchel hole, and base. The horn is used for shaping curves, while the face is used for most of the work. The step is a small, unhardened shelf or table that is not used for shaping metal. The hardy hole and pritchel hole are used for holding tools such as the anvil cutter or chisel.