Gold - A short introduction

Gold was one of the first metals used by humans and archaeological evidence suggests that gold mining dates over 7,000 years back in history. In many pre-historic religions, gold was synonymous with the Sun and became an important metal for jewellery and religious ornaments. Around 700BC gold started to become of economic importance and was soon used for coins. Unlike any other chemical element, gold shaped human history profoundly: It lead to the formation of big cities, led to wars, countries declared their independence and huge numbers of people followed the famous gold rushes.

Production, Mining, Recovery

The easiest way to find gold is in some riverbeds where a technique called panning can be utilised to separate sand and gravel from the much denser gold. It is however a labour intensive process and only makes economic sense if labour is cheap or gold is abundant in such sources.

Most gold nowadays is dug up in either open-pit or underground mines. The seven deepest mines on earth are all South African gold mines with the deepest one surpassing the 4km mark recently. Those mines need to be air-conditioned to make it bearable for humans to work in those hot underground conditions. The gold content in the ore is normally low and each gram of gold requires the movement of 1 tonne of ore, or to put it in relative terms: One million times more rock needs to be extracted for each unit of gold to be recovered.

Due to the high price and importance gold is often recycled and recovered from discarded jewellery and electronic goods. Other potential or future sources of gold are the water treatment plants of big cities where precious metals like silver and gold can be found in traces in the residues. Modern science and technology can transform other metals (mainly mercury and platinum) into golds by using particle accelerators or nuclear reactors, but those methods are too expensive to be commercially exploited.

It is estimated that all the gold that has ever be mined throughout human history is approximately 183,600 tonnes. This equates to a cube with an edge length of 21m – worth approximately six trillion British pounds (dependent on actual gold price). Written out, that is £6,000,000,000,000!

Uses of Gold

Most gold produced in these days is used in jewellery (50%) followed by its use as an investment (40%) with the remainder for industrial applications (10%). As for industrial applications, a large percentage is used in Japan's electronic industry. Most households will find gold at places like smartphones, plating for connectors, computers, etc. And it is even used in the spacesuits of astronauts.

Now turning our attention to jewellery, there are two other important topics that need to be discussed: Fineness and Colour.

Fineness

Gold is normally alloyed to increase its hardness, change its colour or alter the characteristics of it depending on the need. The fineness of gold is measured in carats which is a relative measure of the gold content compared to other metals in the alloy. One carat is 1/24 part of the total, thus 24ct gold is considered pure gold, or 99% purity or better. Some popular and historic gold contents are shown in the following table:

The above values for gold content are the MINIMUM needed in order that an article can be marked as such. If it falls short of the minimum gold content, it can be hallmarked with the next lowest standard (if applicable). For example, a gold content of 76.0% in a ring would be marked as 18ct wheras 74.9% would be downgraded to 14ct.

Pure gold jewellery is rare in Western countries, as gold in its pure form is a very soft metal. It is normally alloyed to make it harder and increase its durability.

In the UK, it is illegal to sell or describe any item as Gold, unless it is hallmarked or it is under the exemption weight of 1.0g!

The colour of Gold

When asked what colour gold has, Yellow is the first answer that springs to mind. But gold is not truly yellow and it has hints of brown, yellow and orange. Gold has a metallic lustre that reflects its surroundings and this is an other factor that makes it hard to establish the colour of gold.

So far for pure gold. Once gold is alloyed with other metals, a change in colour is inevitable. The resulting colour depends on the metals and their abundance in the alloy. Thus, two items being both made from 18ct gold can have completely different colours despite both use 75% gold. This is best seen when you compare 18ct White Gold to 18ct Yellow Gold. However, even yellow gold does not necessarily match the “yellowness” of an other item made from yellow gold of the same fineness. This can cause a problem, if gold components on a piece of jewellery should match in colours (e.g. a clasp of a chain, etc.). It is therefore necessary to use gold sample plates to achieve a uniform colour when matching is important.

Gold can come in many colours. The most common ones are Yellow, White and Rose Gold, but it's also possible to make gold green, red, blue, purple, grey, pink, brown or black, although some are normally not used for jewellery as they are hard to work with. Most white gold alloys have been developed after the Second World War as a platinum substitute in the U.S. Before the war, platinum diamond rings were popular but when platinum was declared a strategic metal during the war in the U.S., it could no longer be used in jewellery. In the early 1960's, yellow gold became a popular choice for diamond rings and due to the rise in popularity of platinum, white gold is more frequently found again, together with silver and palladium as materials for diamond rings. An other way of changing the colour of gold is by plating and the most popular metal used for it is rhodium.

White gold from the U.S. May be alloyed with nickel. Most European countries prohibit the use of nickel in jewellery due to a high percentage of people being allergic to it and jewellery bought in Europe should be nickel-free.

Now that you are equipped with some basic facts about gold and what to look out for, you can now admire the beauty of gold jewellery in our shop – all hallmarked of course.