9ct vs 18ct Gold: What Is the Difference?

9ct vs 18ct Gold: What Is the Difference?

When buying gold jewellery, you will often see descriptions such as 9ct, 14ct, 18ct or 22ct gold. These numbers refer to the proportion of pure gold within the metal, but understanding what that means can make choosing between different pieces much easier.

Gold in its pure form is 24 carat. For jewellery, it is commonly combined with other metals to create alloys with different properties, colours and levels of gold content.

At Walter Bull & Son in Cirencester, we see gold jewellery in many different forms across our new and pre-owned collections. Here is our guide to understanding some of the most common gold carats you may encounter.

What Does Carat Mean in Gold?

When discussing gold, carat describes its purity.

Pure gold is described as 24ct. A piece of 18ct gold therefore contains 18 parts gold out of 24, while 9ct gold contains 9 parts gold out of 24.

You may also see gold described using a three-digit fineness number within a hallmark.

For example, 9ct gold has a fineness of 375, meaning it contains 375 parts of pure gold per thousand. For 18ct gold, the equivalent fineness is 750.

What Is 9ct Gold?

9ct gold contains 37.5% pure gold, with the remainder consisting of other metals within the alloy.

It is widely used for jewellery in the UK and can be found across everything from chains and bracelets to earrings, pendants and rings.

If a piece of UK-hallmarked gold jewellery carries a 375 fineness mark, this indicates 9ct gold.

The exact appearance of 9ct gold can vary depending on the metals used within its alloy and whether the piece is yellow, white or rose gold.

What Is 14ct Gold?

14ct gold contains approximately 58.5% pure gold.

Although particularly common internationally, 14ct gold can also be encountered in jewellery sold in the UK, especially in pre-owned and internationally made pieces.

The corresponding fineness mark is typically 585.

If you regularly look at older or pre-owned jewellery, you may therefore encounter 14ct pieces alongside the more familiar 9ct and 18ct gold.

What Is 18ct Gold?

18ct gold contains 75% pure gold.

Its fineness mark is 750, which is commonly found stamped within fine gold jewellery.

18ct gold is widely used for high-quality rings, necklaces, bracelets, earrings and other jewellery. It is also frequently used in diamond and coloured gemstone pieces.

As with other gold carats, 18ct gold can be produced in different colours depending on the alloy.

What Is 22ct Gold?

22ct gold contains approximately 91.6% pure gold and may carry a 916 fineness mark.

Because of its high gold content, yellow 22ct gold has a particularly rich colour.

It is softer than lower-carat gold alloys, however, which means its suitability depends on the type and design of jewellery being made.

Is 18ct Gold Better Than 9ct Gold?

It is more useful to think of 9ct and 18ct gold as different materials rather than simply describing one as better.

18ct gold contains twice the proportion of pure gold found in 9ct gold, giving it a higher intrinsic gold content.

However, factors such as the type of jewellery, how it will be worn, your budget and your preferred appearance can all influence which is most suitable.

When comparing individual pieces, craftsmanship, design, condition and any diamonds or gemstones should also be considered alongside the carat of the gold.

What Is Yellow Gold?

Yellow gold retains the warm colour most commonly associated with gold.

Because pure gold is naturally yellow, other metals are added to create a workable alloy while maintaining its characteristic golden appearance.

The precise shade can vary depending on the carat and composition of the alloy.

This is why two pieces described as yellow gold may not always be exactly the same shade when placed next to one another.

What Is White Gold?

White gold is created by combining gold with other metals to produce a paler, whiter alloy.

Many pieces of white gold jewellery are also rhodium plated to create the bright white finish people commonly associate with the metal.

Over time, this plating can wear, particularly on jewellery worn frequently. This can reveal the slightly warmer natural colour of the white gold underneath.

White gold jewellery can be professionally replated when required.

What Is Rose Gold?

Rose gold gets its distinctive warm pink tone from the metals used within its alloy, particularly copper.

The amount and composition of these additional metals influence the finished shade.

Rose gold has been used in jewellery for many years and can be found in both contemporary pieces and older pre-owned designs.

Does Gold Carat Affect Colour?

It can.

Because higher-carat yellow gold contains a greater proportion of pure gold, it can have a richer yellow appearance than lower-carat alloys.

However, colour is also influenced by the other metals used within the alloy, so carat alone does not determine the exact shade.

This is particularly relevant when comparing jewellery side by side or when trying to match a new piece with jewellery you already own.

How Can You Tell What Carat Your Gold Is?

One of the first places to look is the hallmark.

Depending on the piece, you may find a small series of marks inside a ring, near the clasp of a necklace or bracelet, or in another discreet position.

Common fineness marks include:

375 for 9ct gold

585 for 14ct gold

750 for 18ct gold

916 for 22ct gold

Hallmarks can contain additional information beyond the gold fineness, including an assay office mark and sponsor's mark.

Older, foreign or heavily worn jewellery may have different or difficult-to-read markings, so an unclear stamp should not be relied upon alone when identifying a piece.

Which Gold Should You Choose?

The right choice depends on the jewellery and your own preferences.

Consider the colour you prefer, how regularly the piece will be worn, its design and the type of jewellery you are buying.

You may also want to consider the other jewellery you wear regularly. If you already wear an 18ct yellow gold wedding ring, for example, you may want another ring to have a similar colour and appearance.

Seeing different gold alloys in person can make these differences much easier to understand.

Gold Jewellery in Cirencester

At Walter Bull & Son, we regularly have gold jewellery in a variety of carats and colours across our new and pre-owned collections.

Our selection includes yellow, white and rose gold jewellery, from everyday pieces through to diamond and coloured gemstone designs.

Visit Walter Bull & Son in Cirencester to explore our current gold jewellery, or browse our website to see selected pieces available online.