Gold

Of all the minerals mined from the Earth, none is more useful than gold. Its usefulness is derived from a diversity of special properties.

Gold conducts electricity, does not tarnish, is very easy to work, can be drawn into wire, can be hammered into thin sheets, alloys with many other metals, can be melted and cast into highly detailed shapes, has a wonderful color and a brilliant metallic luster.

Uses of Gold in Electronics

The most important industrial use of gold is in the manufacture of electronics. Solid-state electronic devices use very low voltages and currents which are easily interrupted by corrosion or tarnish at the contact points.

Gold is the highly efficient conductor that can carry these tiny currents and remain free of corrosion. Electronic components made with gold are highly reliable. Gold is used in connectors, switch and relay contacts, soldered joints, connecting wires and connection strips.

A small amount of gold is used in almost every sophisticated electronic device. This includes cell phones, calculators, personal digital assistants, global positioning system (GPS) units, and other small electronic devices. Most large electronic appliances such as television sets also contain gold.

One challenge with the use of gold in very small quantities in very small devices is loss of the metal from society. Nearly one billion cell phones are produced each year, and most of them contain about fifty cents worth of gold.

Their average lifetime is under two years, and many are not being recycled. Although the amount of gold is small in each device, their enormous numbers translate into a lot of unrecycled gold.

Uses of Gold in Computers

Gold is used in many places in the standard desktop or laptop computer. The rapid and accurate transmission of digital information through the computer and from one component to another requires an efficient and reliable conductor.

Gold meets these requirements better than any other metal. The importance of high quality and reliable performance justifies the high cost.

Edge connectors used to mount microprocessors and memory chips onto the motherboard and the plug-and-socket connectors used to attach cables all contain gold. The gold in these components is generally electroplated onto other metals and alloyed with small amounts of nickel or cobalt to increase durability.

Uses of Gold in Dentistry

How would iron work as a dental filling? Not very well… your dentist would need blacksmithing tools, your smile would be rusty a few days after a filling, and you would need to get used to the taste of iron.

Even at much higher expense, gold is used in dentistry because of its superior performance and aesthetic appeal. Gold alloys are used for fillings, crowns, bridges, and orthodontic appliances. Gold is used in dentistry because it is chemically inert, nonallergenic, and easy for the dentist to work.

Gold is known to have been used in dentistry as early as 700 B.C. Etruscan “dentists” used gold wire to fasten replacement teeth into the mouths of their patients. Gold was probably used to fill cavities in ancient times; however, there is no documentation or archaeological evidence for this use of gold until a little over 1000 years ago.

Gold was much more generously used in dentistry up until the late 1970s. The sharp run-up of gold prices at that time motivated the development of substitute materials. However, the amount of gold used in dentistry is starting to rise again. Some motivation for this comes from concerns that less inert metals might have an adverse effect on long-term health.

Medical Uses of Gold

Gold is used as a drug to treat a small number of medical conditions. Here are examples:

Injections of weak solutions of sodium aurothiomalate or aurothioglucose are sometimes used to treat rheumatoid arthritis.

Particles of a radioactive gold isotope are implanted in tissues to serve as a radiation source in the treatment of certain cancers.

Small amounts of gold are used to remedy a condition known as lagophthalmos, which is an inability of a person to close their eyes completely. This condition is treated by implanting small amounts of gold in the upper eyelid. The implanted gold “weights” the eyelid, and the force of gravity helps the eyelid close fully.
Radioactive gold is used in diagnosis. It is injected in a colloidal solution that can be tracked as a beta emitter as it passes through the body. Many surgical instruments, electronic equipment, and life-support devices are made using small amounts of gold. Gold is nonreactive in the instruments and is highly reliable in electronic equipment and life-support devices.

Uses of Gold in Aerospace

If you are going to spend billions of dollars on a vehicle that when launched will travel on a voyage where the possibility of lubrication, maintenance and repair is absolutely zero, then building it with extremely dependable materials is essential. This is exactly why gold is used in hundreds of ways in every space vehicle that NASA launches.

Gold is used in circuitry because it is a dependable conductor and connector. In addition, many parts of every space vehicle are fitted with gold-coated polyester film. This film reflects infrared radiation and helps stabilize the temperature of the spacecraft. Without this coating, dark-colored parts of the spacecraft would absorb significant amounts of heat.

Gold is also used as a lubricant between mechanical parts. In the vacuum of space, organic lubricants would volatilize and they would be broken down by the intense radiation beyond Earth’s atmosphere. Gold has a very low shear strength, and a thin film of gold between critical moving parts serves as a lubricant – the gold molecules slip past one another under the forces of friction and that provides a lubricant action.