© AMNH / Craig Chesek
Gold leaf sample: Gold is the most malleable naturally occurring metal. Gift of The Gold Leaf Company.
No Other Metal or Mineral Measures Up to Gold
Gold's beauty, value and its many other unique qualities make it the material of choice in many industries. Most gold--78 percent of the yearly gold supply--is made into jewelry. Other industries, mostly electronics, medical and dental, require about 12 percent. The remaining 10 percent of the yearly gold supply is used in financial transactions.
Gold is used as a contact metal in the electronics industry as it is a good conductor of both electricity and heat.
The word "gold" most likely has its origins in the Indo-European word ghel, meaning "yellow." The chemical symbol of gold, Au, is short for the Latin word for gold, aurum, meaning "glowing dawn."
© AMNH / Craig Chesek
Gold wire: Gold is ductile: it can be drawn out into the thinnest wire.
Gold conducts heat and electricity. Copper and silver are the best conductors, but gold connections outlast both of them because they do not tarnish. It is not that the gold lasts longer, but that it remains conductive for a longer time.
Gold is ductile: It can be drawn out into the thinnest wire. One ounce of gold can be drawn into 80 kilometers (50 miles) of thin gold wire, five microns, or five millionths of a meter, thick. This sample is 0.20 millimeters (0.008 inches) in diameter.
© AMNH / Denis Finnin Apollo 11 Space Helmet Replica.
Gold is highly reflective of heat and light. The visors of astronauts' space helmets receive a coating of gold so thin (0.00005 millimeters, or 0.000002 inches) that it is partially transparent. The astronauts can see through it, but even at that thinness the gold film reduces glare and heat from sunlight.
Gold is prized for its beauty. Jewelers and metalsmiths value it as a metal that can be embossed, hammered, cast, stretched or twisted.
© AMNH / Denis Finnin
The Gold Room.
Gold is malleable, so it can be flattened into extremely thin sheets. The walls of the Gold Room are covered with approximately 28 square meters (300 square feet) of 23-karat gold leaf representing 3 ounces of gold metal. Gold leafing--also known as gilding--is an ancient technique. Traditional artisans beat raw gold between pieces of leather until it was almost too thin to be seen. One ounce of gold may be hammered thin enough to cover more than 9 square meters (96.9 square feet) of a surface. The gold leaf may be only 0.18 microns (seven millionths of an inch) thick; a stack of 7,055 sheets would be no thicker than a dime.