When I started putting gold aside for my daughters, I asked myself the obvious question, like everyone does: if I'm buying gold, I might as well get the purest, right? 24-carat, "real" gold, the kind in bullion. I quickly understood that for a piece you wear every day, it was a false good idea. And that if all of Europe and the whole Maghreb settled on 18-carat gold, it wasn't by chance.
Purer doesn't mean better
Pure gold, true 24-carat, is soft. Really soft: you can mark it with a fingernail. It's gorgeous sitting in a safe as a bar, but on a ring you wear every day — one that knocks against door handles and the steering wheel — it bends and scratches within months.
To make jewellery that holds up, gold is mixed with other metals (copper, silver, sometimes zinc or palladium). That mix is called an alloy, and it sets the "fineness": the percentage of pure gold left in the metal.
Here are the finenesses you'll come across, and where:
| Fineness | Pure gold | Hallmark | Where you see it |
|---|---|---|---|
| 24 carat | 99.9% | 999 | Bars, coins |
| 22 carat | 91.7% | 916 | India, Gulf |
| 18 carat | 75% | 750 | Europe, Maghreb |
| 14 carat | 58.5% | 585 | Northern Europe |
| 9 carat | 37.5% | 375 | The « cheap » gold |
18-carat is 75% gold, 25% alloy. Enough gold to keep the colour, the value and the nobility of the metal; enough alloy for the piece to be solid, to survive daily wear and last for years without deforming. It's exactly the balance point.
Why Europe settled on 18
In France, the hallmarking system officially recognises several finenesses, but 750 thousandths (18-carat) became the reference for jewellery. The eagle's-head hallmark you see stamped into second-hand gold is exactly that: the 18-carat mark (I explain how to spot it in 30 seconds). Push open the door of a regular jeweller in France and ask for "real gold", and they'll show you 18-carat by default.
It's not a French quirk: it's simply the fineness that holds up for an object meant to be worn AND to keep its value. 14-carat exists (you see a lot of it in Germany and Northern Europe), but at only 58.5% gold it already slips as a store of value. And 9-carat, at 37.5%, is another story — I wrote a whole article about it, because to me it's simply no longer investment gold.
And the Maghreb in all this?
Here I'm speaking from the inside, because it's my culture. Where I'm from, gold isn't a gadget: it's the women's safe haven, what you give at the birth of a daughter, what's passed down from mother to daughter, what you accumulate across weddings. It's not decoration, it's savings you carry on you.
And in that logic, 18-carat is everywhere in everyday Maghreb jewellery: it wears well, it's handed down, it keeps its value. People sometimes go higher, towards 21 or 22-carat, especially for ceremonial pieces or when moving closer to Gulf and Asian codes, where investment gold is thought of in 22-24 carat — very yellow, very pure, resold by weight without a second thought. That 22-carat carries a « 916 » marking rather than an eagle head — I decode those foreign hallmarks in a separate article.
That's where the real cultural difference lies: in countries where gold serves first as pure savings resold by weight, you raise the fineness (22-24). In Europe — and for much of daily life in the Maghreb — where gold has to be a piece you wear while remaining a store of value, 18-carat stays the best of both worlds.
What it changes when you buy
If you're buying gold as a pleasure-piece, take whatever fineness you like, treat yourself. But if the idea behind it, even partly, is to secure your money in a piece you can pass on or resell one day, then 18-carat is the right default reflex:
- It keeps its value. At 75% gold, the buy-back by weight stays worthwhile, and the piece can be resold as-is on the second-hand market to someone who'll wear it.
- It lasts. You can wear it every day for thirty years without it deforming. A piece you keep is a piece that crosses generations.
- It's easy to compare. Since it's the standard fineness in Europe, you can put two 18-carat pieces side by side and compare their price per gram directly, without recalculating the real gold share each time.
That last reason is exactly why, on OrOGramme, I only show 18-carat and above by default. When everything is the same fineness, the price per gram of the piece is enough to spot the good deal. As soon as you mix finenesses, the maths gets tricky — and that's precisely the work I'd rather spare you.
Eleven French second-hand 18-carat gold shops, normalised per gram and sorted by the best deal on the metal.
To wrap up
Purer isn't always better: for a piece you wear, 24-carat is too fragile, and below 18 you lose too much value. 18-carat isn't a budget compromise — it's the exact point where gold stays a real store of value while being solid and wearable. That's why it won, on both sides of the Mediterranean.
I'm telling you what I learned buying for myself and for my daughters. Make your own choices for your own situation — but if you're unsure about fineness, start by looking at 18-carat.
Sources for the figures cited:
- French hallmarking rules for precious metals (750 thousandths / 18-carat stamp): douane.gouv.fr, accessed 8 June 2026
- Why I filter out 9-carat (OrOGramme article): orogramme.com
- Legal framework for the guarantee of gold, silver and platinum (articles 183 to 214): Légifrance, accessed 8 June 2026
- History of precious-metal guarantee in France (since 1260, eagle-head hallmark since 1838): douane.gouv.fr, accessed 8 June 2026
- Carat ↔ thousandths conversion and pure-gold percentages (999, 916, 750, 585, 375): Fineness — Wikipedia, accessed 8 June 2026