The first gold coins were minted under the order of King Croesus of Lydia (a region of present-day Turkey) in about 560 BC. Gold coins were commonly used in transactions up through the early 1900's when paper currency became a more common form of exchange. Gold coins were issued in two types of units. Some were denominated in units of currency, such as dollars, while others were issued in standard weights, such as ounces or grams.

Today gold coins are no longer in wide use for financial transactions. However, gold coins issued in specific weights are popular ways for people to purchase and own small amounts of gold for investment. Gold coins are also issued as "commemorative" items. Many people enjoy these commemorative coins because they have both a collectable value and a precious metal value.

Special properties of gold make it perfect for manufacturing jewelry. These include: very high luster; desirable yellow color; tarnish resistance; ability to be drawn into wires, hammered into sheets or cast into shapes. These are all properties of an attractive metal that is easily worked into beautiful objects. Another extremely important factor that demands the use of gold as a jewelry metal is tradition. Important objects are expected to be made from gold.

Pure gold is too soft to stand up to the stresses applied to many jewelry items. Craftsmen learned that alloying gold with other metals such as copper, silver, and platinum would increase its durability. Since then most gold used to make jewelry is an alloy of gold with one or more other metals.

The alloys of gold have a lower value per unit of weight than pure gold. A standard of trade known as "karatage" was developed to designate the gold content of these alloys. Pure gold is known as 24 karat gold and is almost always marked with "24K". An alloy that is 50% gold by weight is known as 12 karat gold (12/24ths) and is marked with "12K". An alloy that contains 75% gold by weight is 18 karat (18/24 = 75%) and marked "18K". In general, high karat jewelry is softer and more resistant to tarnish while low karat jewelry is stronger and less resistant to tarnish - especially when in contact with perspiration.

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 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 very few are currently recycled. Although the amount of gold is small in each device, their enormous numbers translate into a lot of unrecycled gold.

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 1970's. 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.