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.
Lithium as an investment
Lithium metal is an extremely soft, highly reactive, and flammable element. It is most frequently found in deposits such as spodumene and pegmatite minerals, with larger resources in the U.S., Canada, Australia, China, Zimbabwe, and Russia. Lithium possesses a unique chemical profile making it the lightest metal in the periodic table and the least dense solid element. Its atomic number is 3 (right behind helium at 2 and hydrogen at 1), and its density is just 0.53 kg/L. This alkali metal is probably best-known for its wide use in lithium batteries common in all sorts of electronics devices. Other industrial applications include manufacturing heat-resistant glass and ceramics, high-performance alloys used in aircraft, and lubricating greases. Lithium deuteride is used in staged thermonuclear weapons as a fusion fuel. Compounds of lithium are also used as mood stabilizing drugs in psychiatry. The breakdown of the global end-use lithium markets is estimated as follows: ceramics and glass, 31%; batteries, 23%; lubricating greases, 9%; air treatment, 6%; primary aluminum production, 6%; continuous casting, 4%; rubber and thermoplastics, 4%; pharmaceuticals, 2%; and other uses, 15%.