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The Gold Guide – Everything You Need to Know about Gold!

There is something incredibly special about gold and in its purest form there is nothing else like it on the planet and in this guide, I am going go through everything that you need to know about the most precious of precious metals.

Why is Gold so Valuable?

While not the most valuable of all the metals, gold is the most unique and there are a few reasons for this and for this section I am just talking about metals that appear in the periodic table.

  1. Nothing else looks like Gold. Every other metal has another that looks very similar but no other metal shares the appearance that gold has.
  2. It is rare and while no where near the rarest, when compared to other metals such as iron, copper and silver, it is very rare.
  3. Gold is completely no reactive. Unlike other metals such as copper or silver, which react with other elements such as oxygen. Gold doesn’t react with anything and pure gold is completely hypoallergenic.
Gold Bars

In industrial applications, it is also a very popular choice for connectors as it not only conducts heat and electricity well but as it is non-reactive, it will outlast other highly conductive metals.

So that is why gold is so valuable and although we think of bullion (gold bars) and jewellery when we think of gold, the majority of the gold that is mined worldwide is actually bought and used in industrial applications, especially electronics.

What is the difference between Carat and Karat?

The simple definition is that:

  • Carat is the unit of measurement we use to weight diamonds and gemstones.
  • Karat is a unit of purity when talking about gold (parts per 1000).

However in the UK, carat is often used for both gold and diamonds/gemstones, the different terms are more widely used in different countries around the world.

You will often also see carat abbreviated to ct, so 18 carat gold will for example be shortened to 18ct.

9ct or 18ct Gold?

While 24 karat (24ct) gold is 99.9% pure but it is not suitable for use in jewellery as it is too soft and a ring for example would soon get bent out of shape. It is for that reason that we mix gold with other alloys to make the metal more suitable for use in jewellery.

In the UK 9ct and 18ct gold are two main karats that are used for jewellery and satisfy two different segments of the jewellery market.

9ct Gold

9ct contains 375 parts per thousands or 37.5% gold and the remaining 62.5% is made of an alloy that normally contains silver and copper but this alloy does vary from manufacturer to manufacturer. As the gold content is quite low, 9ct gold is the cheapest gold that you can buy and is often used in lower end jewellery.

18ct Gold

18ct gold is made of 750 parts per thousand or 75% gold and the remaining 25% is made up of a metal alloy. 18ct gold due to its value and desirability is the most popular choice of gold for engagement rings, fine and high jewellery. 18ct gold is softer than 9ct due to the higher gold content.


Any piece of gold jewellery weighing over 1g in the UK must be hallmarked, but what is a hallmark?

A hallmark is a stamp from one of the four UK assay offices (London, Birmingham, Sheffield and Edinburgh), which is made up of different emblems, which include:

  • Sponsors Mark – Who sent the piece for assay, can be an individual or a company.
  • Standard Mark – the purity of the metal in parts per 1000.
  • Assay Office Mark – This is the symbol of the office that assayed the piece (London – Leopards Head, Birmingham – Anchor, Sheffield – Rose, Edinburgh – Castle).
  • Date Letter – The letter and font type of the letter denote the date that the piece was stamped (since 1998, the date letter has been optional).
  • Traditional Fineness Mark (Optional) – The different symbols used for the traditional mark denotes the type of metal that was being hallmarked with the Crown symbol being used for gold pieces.

Yellow, White or Rose Gold?

You may have seen yellow gold, white gold and rose gold advertised but are not sure what the difference is between the three.

Yellow Gold

Yellow gold really is just gold and it is the colour we think of when we picture a solid gold bar but as I said above, pure gold (24ct) is too soft for use in jewellery, so they need to mix with an alloy of other metals to produce a metal that is useable in jewellery but also is instantly recognised as gold.

Two of the main metals used in this alloy are copper and silver as when combined, they produce a colour that is similar to that of pure gold but the exact formulas and metals not only vary between different karats but also different manufacturers and is often a heavily guarded secret.

Yellow Gold Flush Set Eternity Ring

This is why two yellow gold pieces can vary in colour as one manufacturer may use more silver, which results in a brighter yellow colour whereas other put more copper in which gives a darker yellow colour, that sometimes has a slight reddish tint.

White Gold

White Gold Princess Cut Half Eternity Ring

White gold is a very popular choice, especially for engagement rings and is an alternative for other white metals such as Platinum and Palladium.

Production of white gold is done by mixing gold with an alloy of white metals, in 9ct gold, this is often mostly silver but generally also includes some other white metals.

In 18ct gold, the alloy that the gold is mixed with is usually a combination of Silver and Palladium and the higher the percentage of palladium in the mix (usually above 13%), the whiter the colour of the metal becomes.

However, unlike either of the other types of gold, a large percentage of white gold jewellery is actually Rhodium plated and this can be easily spotted by the bright, highly reflected surface of some white gold jewellery. While it looks amazing when first bought, this plating will wear off over time and reveal the true colour of the gold underneath. Fortunately, most jewellers offer a rhodium plating service.

Much of the mass produced 18ct white gold jewellery usually has a very creamy yellow colour under the rhodium plating as they use a mixture that has a relatively low palladium content.

High palladium content white gold often doesn’t need to be rhodium plated as the colour of the gold is similar to that of platinum or palladium and while it doesn’t have that bright, highly reflective finish, the colour of the gold will remain over time.

Rose Gold

Rose gold, sometimes called red gold, is a colour of gold that often goes in and out of fashion but is currently a very popular option.

Rose gold is probably the simplest of all the golds to manufacture as it is basically a mixture of gold and copper and this produces a very attractive colour with a reddish tint.

Due to the higher copper content, 9ct rose gold has a much stronger red colour than 18ct rose gold and in some cases, the 18ct variety has more of a pinkish colour.

Rose Gold Diamond Pave Set Eternity Ring


So there it is, my guide to wonderful metal that is Gold! I hope that you have learnt something from this guide as I definitely enjoyed writing it and it took me back to where my jewellery journey began all the way back in 2011. To this day, I still think that there is something magical about this unique precious metal. Thank you for reading!

I'm Paul Haywood FGA DGA, a fully qualified Gemmologist and Diamond Grader from the Gemmological Association of Great Britain and a lover of all things jewellery.

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