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Gold fact file

Gold was discovered by man about 6,000 years ago - quite probably the first nugget of gold was picked up by chance from a river bed. By 2,500BC craftsmen were working with it to create precious jewellery and fine treasures. Nuggets of gold have been found weighing from 1oz (28 grams) to a staggering piece that tipped the scales at 2,000oz (56 kilograms) and the innermost coffin in which Tutankhamun lay was lined with 110 kilograms of solid gold.

Recognised throughout the world for its rarity, it is estimated that all the gold in the world, so far refined, could be placed in a single 60 foot cube. Gold is the only naturally yellow metal, named from the old English word for yellow - 'geolo' and it has no oxides so is the only metal that will not tarnish or rust.

Gold is a naturally occurring element in the Earth's crust and can be found in mineral deposits of quartz, copper, silver, pyrite, tellurium and calcite. Gold is brought to the surface of the Earth by volcanic or hydro-thermal action in its molten state, or as a hot gas. It is deposited in reefs, which when weathered, release the gold most frequently into nearby fast running streams. Gold is one of the heaviest elements, so it sinks to the bottom or bedrock of the stream ready to be found by gold panning or mining.

The Californian Gold Rush of 1849 was so alluring to prospective fortune makers that a grid lock of cargo boats was created in San Francisco Harbour and no one left in the port to unload them. Supposedly around half of the world's supply of gold is stored in the United States Treasury Department's gold depository in Fort Knox, Tennessee, which is considered to be one of the most secure buildings in the world.

Gold is used for coating space satellites as it is a good irradiation reflector. It is a soft metal (2.5-3 mohs hardness compared to diamond at 10 mohs) and is highly malleable - it can be beaten or rolled in any direction without cracking or breaking. It is also ductile, for example it can be drawn into fine wire the thickness of a single human hair. 1oz (28 grams) of gold can be beaten out to 300 square feet!

It is estimated there is about 5-6 grams of gold in a million tonnes of sea water, but no effective economic process has (yet) been designed to extract it from this source, and there is even the tiniest trace in human toenails. Today, gold continues to inspire the world’s designers to create beautiful jewellery for us to wear every day.

Carat - the measure of gold's purity

Gold is the perfect partner for the craftsman's tools, due to its ability to be fashioned into virtually any shape. It can also be mixed with other metals such as copper or silver to obtain alloys that are harder and more resistant to wear, or which are suitable for particular uses.

The carat system of measuring the purity of gold derives from an ancient weighing system that used locust tree seeds (which are a consistent size) as a measure. Pure gold is 24 carats; one carat is therefore a24th part weight of the whole, so 18 carat (ct) gold must contain a minimum of 18 parts of pure gold per 24 parts total. 18ct gold jewellery contains twice the proportion of pure gold of a piece crafted from 9ct gold.

Except for those pieces weighing under 1 gram in weight or delicate pieces where hallmarking would cause too much damage, any item sold as gold in the UK must conform to an approved level of purity and be tested by one of the four Assay Offices (London, Birmingham, Sheffield and Edinburgh). Those that pass this test are stamped (or, in recent years laser inscribed) with a hallmark, a system that was first introduced in the 14th century and recognised worldwide as the definitive way of guaranteeing the purity of any piece of gold jewellery. Hallmarking therefore was the very first example of consumer protection legislation.

In the UK, every piece of hallmarked jewellery must reach the minimum standard specified. This is also the case in other countries such as America and throughout Europe; however many other countries have no system or only have one proving average fineness e.g. provided each batch submitted averages the required fineness, individual items may be below the minimum. Gold buyers should therefore think carefully before buying gold in other countries, even if it is hallmarked.


When we think of the colour of gold jewellery, we immediately conjure up images of a rich deep yellow colour, which in ancient times was linked with the sun. However gold can be rose, yellow or white in colour, or even a combination of all three. The colouring is obtained by combining gold with different alloys, such as copper for rose gold or silver for white gold; both add a new dimension to gold jewellery designs. As all hallmarking levels contain an amount of other metals, the original carat can be retained.