Foil (metal)
A foil is a very thin sheet of metal, usually made by hammering or rolling. Foils are most easily made with malleable metals, such as aluminium, copper, tin, and gold. Foils usually bend under their own weight and can be torn easily. The more malleable a metal, the thinner foil can be made with it. For example, aluminium foil is usually about 1/1000 inch (0.03 mm), whereas gold (more malleable than aluminium) can be made into foil only a few atoms thick, called gold leaf. Extremely thin foil is called metal leaf. Leaf tears very easily and must be picked up with special brushes.
Sculpture
Bronze and related copper alloys are the oldest and still the most popular metals for cast metal sculptures; a cast bronze sculpture is often called simply a "bronze". Common bronze alloys have the unusual and desirable property of expanding slightly just before they set, thus filling the finest details of a mold. Their strength and lack of brittleness (ductility) is an advantage when figures in action are to be created, especially when compared to various ceramic or stone materials (see marble sculpture for several examples). Gold is the softest and most precious metal, and very important in jewellery; with silver it is soft enough to be worked with hammers and other tools as well as cast; repoussé and chasing are among the techniques used in gold and silversmithing.