The most malleable pure metal known to man, gold has been prized since the earliest times for its pliability, resistance to tarnish and above all for its beauty. It is mined in two ways, the gold dust or nuggets panned from streams or from ancient river beds, or extracted as flecks or grains from rocks such as quartz. The first king to use gold as currency was the celebrated Croesus of Lydia in about 560 BC, but it has also been used as an ornament and in jewellery for thousands of years, and been a symbol of power and wealth. Gold rushes occurred in the late 19th century as large deposits were discovered in the USA, New Zealand, Australia and Canada, but perhaps most famously in the Witwatersrand in South Africa, which has been the source of about half of all gold ever produced. However, gold is so valuable that the world’s stock remains largely stable, with little consumption of new gold and most gold recycled and reused.
The colour of gold varies according to its purity. Absolutely pure gold is measured as 24 carat, but because at this purity it is too soft for jewellery intended to be durable, it is mixed with other metals. In this way, white gold is produced by adding palladium, nickel or silver to the gold. White gold became popular in the 1920s as an alternative to platinum, and can often be seen in art deco jewellery. It has shown a renaissance of interest, and is now perhaps the most popular gold for engagement and wedding rings. Often white gold is electro-plated with rhodium to increase its brightness and shine.
Did you know?
- A 50th wedding anniversary is known as the golden anniversary.
- The legend of the golden fleece may be a reference to the use in antiquity of fleeces to collect gold dust from alluvial deposits.
- In the Middle Ages, the nobility sometimes used gold flake as a food decoration to demonstrate their wealth or because they believed that such a valuable material must also have health benefits. Gold leaf is still used in foods and some cocktails contain flakes of gold.
- Gold is also used for making solar cells on spacecraft and helmets for moon walkers, as it can store the sun’s energy. It is also used in dentistry, medicine and computers.