What Does 9ct, 14ct & 18ct Gold Mean? A Guide to Gold Purity

You've probably noticed them — tiny numbers and symbols stamped inside your ring, on the clasp of your necklace, or tucked behind the pin of a brooch. Maybe you've spotted 375, 750, or 585 and wondered what on earth they mean. Perhaps you've inherited a piece and you want to know whether the gold is genuine before you wear it, sell it, or insure it.

These little stamps are called hallmarks, and they're one of the oldest forms of consumer protection in the world — dating back over 700 years in the UK. They tell you exactly what your gold is made of, where it was tested, and in many cases, when it was made.

Here, we're going to break it all down: what the different gold carats actually mean, how to read a UK hallmark, and how to choose the right gold purity for the jewellery you're buying or wearing. Whether you're shopping for an engagement ring, valuing a family heirloom, or just curious about what's stamped inside your favourite piece, this guide has you covered.

What Does "Carat" Mean in Gold?

When we talk about gold carat (abbreviated as ct in the UK), we're talking about purity — the proportion of pure gold in the metal compared to other metals mixed in.

Pure gold is 24 carat. It's beautiful, but it's also very soft — too soft, in fact, for most jewellery. A ring made from pure 24ct gold would scratch, dent, and bend far too easily for everyday wear. So jewellers mix (or alloy) pure gold with other metals — typically silver, copper, zinc, or palladium — to make it harder, more durable, and suitable for jewellery that lasts a lifetime.

The carat number tells you how many parts out of 24 are pure gold:

So when you see 375 stamped inside a ring, it means the metal is 375 parts per thousand pure gold — or 37.5%. That's 9ct gold. A stamp of 750 means 75% pure gold — that's 18ct.

Quick note: "carat" for gold purity is different from "carat" used for diamond weight. Same word, completely different measurements. Gold carat = purity. Diamond carat = weight.

9ct vs 14ct vs 18ct Gold — What's the Actual Difference?

This is probably the most common question we get asked in the shop, and the honest answer is: it depends on what matters most to you. Each carat has genuine advantages.

9ct Gold (375)

9ct gold is the most popular choice in the UK and has been a legal standard here since 1854. It contains 37.5% pure gold mixed with other metals, which makes it the most affordable option — but also the most hardwearing.

Why people choose 9ct:

• Durability. The higher proportion of alloy metals makes 9ct gold harder and more resistant to scratching than higher carats. It's an excellent choice for jewellery you plan to wear every day — think wedding bands, everyday rings, bangles, and chains that take a bit of a knock.
• Price. 9ct gold costs significantly less per gram than 18ct, which means you can often get a larger or more detailed piece for the same budget.
• Appearance. 9ct yellow gold has a slightly lighter, softer yellow tone compared to 18ct. Some people genuinely prefer this subtler colour, especially for more contemporary or casual pieces.

Things to be aware of: Because 9ct gold contains more alloy metals, it can occasionally cause reactions in people with very sensitive skin (particularly if the alloy contains nickel, though this is now tightly regulated in the UK). Over many years, it may also tarnish slightly — though this is easily polished away.

Browse our 9ct Gold Collection →

14ct Gold (585)

14ct gold is the standard across much of Europe and the United States, though it's less common as a UK tradition. It sits neatly between 9ct and 18ct in terms of both purity and price — 58.5% pure gold — and offers a good balance of durability and richness of colour.

Why people choose 14ct:

• A warmer, richer yellow than 9ct, but still hard-wearing enough for everyday use.
• A middle-ground price point.
• Common in European antique jewellery — if you've inherited a continental piece, it may well be 14ct.

Interesting historical note: Before 1932, the UK also used 12ct and 15ct gold standards. Both were abolished and replaced by 14ct. If you find a piece hallmarked 12ct or 15ct, it was almost certainly made before 1932 — which makes it a genuine antique. We see these come through the shop regularly, and they always have a story to tell.

18ct Gold (750)

18ct gold is the traditional choice for fine jewellery and engagement rings. At 75% pure gold, it has a deep, warm, rich yellow colour that's unmistakably luxurious — and it's the standard used by most high-end and heritage jewellery houses worldwide.

Why people choose 18ct:

• Colour. That deep, saturated gold tone. Once you've seen 9ct and 18ct side by side, the difference is immediately clear.
• Prestige. It's the traditional choice for engagement rings, wedding rings, and significant jewellery gifts. There's a reason antique jewellery from the Georgian and Victorian eras is almost always 18ct or higher — it was the standard of quality.
• Skin-friendliness. The higher gold content means fewer alloy metals, which generally makes 18ct gold better suited to sensitive skin.
• Value. 18ct gold holds its value well over time, both as gold and as jewellery.

Things to be aware of: 18ct gold is softer than 9ct, so it's more prone to surface scratches — though these develop into a beautiful patina over time, and a jeweller can always repolish the piece. It also costs more per gram.

Shop our engagement ring collection (9ct & 18ct) →

22ct and 24ct Gold

22ct gold (91.6% pure) is traditional for wedding bands in the UK and remains the standard in South Asian and Middle Eastern jewellery markets. It has a deep, rich, almost orange-yellow tone. 24ct gold (99.9% pure) is used primarily for gold bars and coins rather than jewellery, because it's simply too soft for most wearable pieces.

Gold Colour: Yellow, White, and Rose

The carat tells you how much pure gold is in the piece, but the colour of the gold depends on which metals are mixed in.

• Yellow gold: Pure gold alloyed with silver and copper, maintaining the traditional warm golden colour.
• White gold: Pure gold alloyed with palladium or nickel (and often rhodium-plated for extra brightness). Popular for engagement rings and contemporary jewellery. White gold can be 9ct, 14ct, or 18ct — the carat still refers to gold purity, regardless of colour.
• Rose gold: Pure gold alloyed with a higher proportion of copper, giving it that distinctive warm pink tone. Rose gold has become hugely popular in recent years, and we have a growing range of pieces in both 9ct and 18ct rose gold.

It's worth noting that white gold will naturally yellow over time as the rhodium plating wears — this is normal and your jeweller can re-plate it for you. It doesn't mean the gold is deteriorating. Our repair and resizing service includes rhodium replating.

How to Read a UK Gold Hallmark

Every piece of gold jewellery sold in the UK that weighs more than one gram must, by law, be independently tested and hallmarked by one of the four UK Assay Offices. This has been the case, in various forms, since King Edward I introduced the first hallmarking statute in 1300 — making the UK hallmarking system one of the most rigorous and long-standing in the world.

A full UK hallmark on a gold piece typically includes these marks, stamped in a row:

1. The Sponsor's Mark (Maker's Mark)

This identifies the person or company who submitted the piece for hallmarking. It's usually a set of initials inside a distinctive shaped outline — each maker registers their own unique mark. On antique pieces, identifying the maker's mark can help you trace the jeweller who crafted it, which can significantly affect the piece's value and interest to collectors.

2. The Fineness Mark (Purity)

This is the number that tells you the gold purity — 375 (9ct), 585 (14ct), 750 (18ct), 916 (22ct), or 999 (24ct). On older pieces (pre-1999), you may also see the traditional crown symbol alongside the fineness number — the crown was the historic English mark for gold.

3. The Assay Office Mark

This symbol tells you where the piece was tested. There are four Assay Offices currently operating in the UK:

On antique jewellery, you may encounter marks from Assay Offices that have since closed — Chester (three wheat sheaves and a sword), Exeter (a three-towered castle), Norwich (a castle over a lion), and Glasgow (a tree, fish, bell, and bird). These closed-office marks can help date a piece precisely and are a fascinating part of the jewellery's history. We wrote more about this in our guide to dating antique jewellery.

4. The Date Letter (Optional since 1999)

Before 1999, every hallmarked piece carried a date letter — a single letter of the alphabet in a specific typeface and shield shape that changed every year. This is incredibly useful for dating jewellery: if you can identify the Assay Office mark and the date letter, you can pinpoint the exact year a piece was hallmarked.

Since 1999, the date letter has been optional, so many modern pieces won't have one. But on antique and vintage jewellery, it's one of the most valuable clues you have.

What If My Gold Has No Hallmark?

There are several legitimate reasons why a gold piece might not carry a UK hallmark:

• It weighs under one gram. Very small items — delicate earring studs, for example — are exempt from compulsory hallmarking in the UK.
• It was made abroad. Jewellery made in countries without mandatory hallmarking (including the United States and parts of Asia) may carry only a karat stamp (e.g., "14K") rather than a formal UK hallmark. This doesn't mean it's not genuine — but it hasn't been independently verified by a UK Assay Office.
• It's very old. Georgian-era jewellery (pre-1837) and small items like brooches and earrings were often legally exempt from hallmarking in earlier centuries.
• The hallmark has worn away. On well-loved, well-worn pieces — especially rings — the hallmark can become illegible over decades of wear.

If you have a piece without a clear hallmark and you'd like to know what it's made of, we can help. Sandy offers free verbal valuations in store — she'll examine the piece, test the metal, and tell you exactly what you have. Find out more about our valuation service →

Which Gold Carat Is Right for You?

There's no single "best" — it genuinely depends on how you plan to wear the piece, your budget, and your personal taste. Here's how we tend to advise customers in the shop:

We always recommend coming in and trying pieces on in different carats so you can see and feel the difference for yourself. There's no substitute for holding a 9ct piece in one hand and an 18ct piece in the other — the difference in colour and weight is something you notice immediately, and most people develop a clear preference quite quickly.

Gold Purity and Antique Jewellery

If you're interested in antique and pre-owned jewellery — and many of our customers are — understanding gold purity becomes even more important, because the standards have changed over the centuries.

A few things worth knowing:

• Georgian jewellery (1714–1837) was almost always made in 18ct or 22ct gold. 9ct didn't become a legal standard until 1854.
• Victorian jewellery (1837–1901) used 9ct, 12ct, 15ct, 18ct, and 22ct gold. Finding a piece marked 12ct or 15ct is a reliable indicator of a piece made between 1854 and 1932.
• Art Deco jewellery (1920s–1930s) shifted heavily toward platinum and white gold, so gold pieces from this era are rarer and often quite distinctive.
• Retro/1940s jewellery returned to yellow and rose gold when platinum was classified as a war-restricted material.

Each era used gold differently, and understanding the purity can help you date, value, and appreciate a piece far more fully. If you'd like to go deeper into era identification, we've written a complete guide to dating antique jewellery by era.

Browse our antique & pre-owned collection →

What Happens to Gold Purity When You Sell or Part-Exchange?

If you're thinking about selling gold jewellery, the carat is the single most important factor in determining its melt value. Higher carat = more pure gold = higher value by weight.

That said, the melt value of a piece (what the gold is worth as raw metal) is often only part of the story. An antique or designer piece may be worth considerably more than its gold content because of its craftsmanship, rarity, or historical significance. A Victorian 15ct gold brooch, for example, might be worth far more to a collector than its scrap gold value.

At Jordans, we always assess pieces for their full value — not just the metal weight. If you have gold jewellery you'd like to sell or part-exchange, Sandy will give you an honest appraisal of both the gold value and the piece's worth as jewellery. No pressure, no obligation.

Find out more about selling your gold →

Frequently Asked Questions

Does 9ct gold tarnish?

9ct gold can develop a slight tarnish over time due to the higher proportion of alloy metals, particularly copper. This is completely normal and nothing to worry about — a gentle polish with a soft cloth or a trip to your local jeweller will restore the shine. 18ct gold is more resistant to tarnishing because of its higher gold content.

Is 9ct gold real gold?

Yes, absolutely. 9ct gold is genuine gold — it contains 37.5% pure gold, which is the minimum legal standard for gold jewellery in the UK. It's hallmarked, independently tested, and every bit as "real" as 18ct or 22ct. The difference is purity, not authenticity.

Can you tell the difference between 9ct and 18ct gold by looking at it?

Yes — when you see them side by side, the difference is quite clear. 18ct yellow gold has a deeper, warmer, more saturated golden colour. 9ct yellow gold is lighter and slightly paler. With white gold the difference is less obvious, especially when both are rhodium-plated, but an experienced jeweller can usually tell.

What does "375" mean on my ring?

It means your ring is 9ct gold — 375 parts per thousand (37.5%) pure gold. This is the UK hallmark fineness number for 9ct gold, and it's the most common hallmark you'll find on gold jewellery in Britain.

What does "750" stamped on jewellery mean?

750 means 18ct gold — 750 parts per thousand (75%) pure gold. This is the fineness mark for 18ct gold in the UK hallmarking system.

Is 18ct gold worth buying for an engagement ring?

We'd say yes — and most of our engagement ring customers agree. The richer colour, the prestige, the durability over decades of daily wear, and the higher resale value all make 18ct gold the traditional and popular choice for engagement rings. That said, 9ct gold engagement rings are beautiful too, and some of our most striking vintage rings are 9ct. Come in and try both — you'll know which feels right.

Read our complete guide to choosing an engagement ring →

Come and See for Yourself

The best way to understand gold purity is to see it, touch it, and try it on. We always have a wide range of pieces across every carat in the shop, and Sandy and the team are always happy to walk you through the differences — no appointment needed, no obligation to buy.

Whether you're shopping for something new, curious about an inherited piece, or thinking about selling gold you no longer wear, we'd love to help.

Jordans Jewellers
29 South Street, Dorchester, Dorset, DT1 1BY
Monday – Saturday, 9:30am – 4:30pm
01305 250413 | enquiries@jordansjewellers.co.uk

Book an appointment with Sandy →

Have a question about gold purity or hallmarks? Drop it in the comments below and we'll answer it.