A chisel is a tool with a cutting edge on its end, for carving and/or cutting a hard material such as wood, stone, or metal. The handle and blade of some types of chisels are made in one piece. In use, the chisel is forced into the material to cut the material. The driving force may be manually applied or applied using a mallet or hammer. In industrial use, a hydraulic ram or falling weight ('trip hammer') drives the chisel into the material to be cut. A gouge, one type of chisel, is used, particularly in woodworking and sculpture, to carve small pieces from the material. Gouges are most often used in creating concave surfaces. A gouge has a 'U'-shaped cross-section.