The first time someone gave me a gold chain, I wore it for months without ever looking inside the clasp. It was when I started reselling my first pieces that I picked up the reflex: before anything else, I look for the hallmark. That tiny stamp pressed into the metal is the only proof that you're really holding gold — and not a pretty piece of gilded copper.
The problem is that nobody teaches us to read it. We look at the piece, find it beautiful, and trust. And that's exactly where you get caught.
This article is about French hallmarks. If your piece carries a numeric marking (« 750 », « AU750 »), an Italian hallmark or another foreign sign, I wrote a separate guide: reading foreign gold hallmarks.
Why the hallmark, and nothing else
When you buy gold, you're not buying a colour or a shine: you're buying precious metal whose value is calculated by the gram. The thing is, gold plating and solid gold look identical to the naked eye. Same shade, same sparkle, sometimes the same weight in hand. The difference can't be seen — it has to be read.
In France, a solid gold piece sold through the official channel must carry a guarantee hallmark: a small symbol struck by the State (via the guarantee office, attached to customs) that certifies the fineness of the metal. It's a precious-metal control system that has existed since the late 18th century, and it's still in force today.
A solid gold piece sold in France necessarily carries a guarantee hallmark. No eagle head, no owl head: no proof.
That's why this little drawing is worth more than all the seller's promises.
The menagerie: which animal for which fineness
The French guarantee hallmark takes the shape of a small animal, and each animal corresponds to a precise fineness (the share of pure gold). The three you'll meet most often in jewellery:
| Hallmark | Fineness | Pure gold | What it means |
|---|---|---|---|
| Eagle head | 750 (18k) | 75% | 18-carat gold, the European reference. Also used for 22-carat. |
| Scallop shell | 585 (14k) | 58.5% | 14-carat gold, more common in Northern Europe. |
| Clover | 375 (9k) | 37.5% | 9-carat gold — the cheap gold I'm wary of (I wrote a whole article about it). |
The eagle head is the one that should flash a little green light when you're aiming for investment: it's 18-carat, the solid fineness, wearable daily, that holds its value. It's also the only one I keep by default on OrOGramme.
And there's a fourth creature, crucial when you buy second-hand:
- Owl head: this hallmark is applied to gold pieces of foreign or undetermined origin, typically second-hand items passing back through French control. It guarantees gold of at least 750 thousandths. If you hunt for second-hand, it's as reassuring a signal as the eagle head.
The owl is also where you tip over into the world of foreign hallmarks — when a piece comes from Italy, the Maghreb or the Gulf, it doesn't necessarily carry a French animal. I decode those markings in another article.
The trap: gold plating passing for gold
This is the point where people get caught the most, and it's exactly what I wanted this article to defuse.
Gold plating is a thin layer of gold deposited on a worthless metal. It stays pretty, it's worth almost nothing on resale. And the trap is that it sometimes carries markings that look like hallmarks and make you believe it's solid gold. The simple rule: gold plating never carries a State guarantee hallmark (no eagle head, no owl head). What it carries instead are mentions or abbreviations:
- "Gold plated", "plaqué or", or a thickness in microns ("3 microns", "10 microns")
- "GP" (gold plated) or "GF" (gold filled), often followed by a fraction and a fineness, like "1/20 14k GF"
- "gilt metal" — there, even the word "gold" has disappeared
The reflex to keep in mind: you're looking for an engraved animal. If all you find is a string of letters, a fraction, or the word "plated", you're not holding a solid gold piece — no matter how much it shines.
The 30-second check (before buying or reselling)
Here's exactly what I do, every time, and it takes less than a minute:
- I find the hallmark. It's always in a discreet spot: the inside of a ring band, the clasp or a link of a chain, the post of an earring. My phone camera at maximum zoom works as a magnifying glass.
- I read the animal. Eagle head = new 18-carat. Owl head = guaranteed second-hand gold. Shell or clover = it's gold, but a lower fineness (up to you whether it interests you). No animal, just "GP / GF / plated" letters = I put the piece back down.
- I spot the lozenge. Next to the guarantee hallmark there's often a second small stamp shaped like a lozenge: it's the maker's mark, the mandatory signature of the French manufacturer. Its presence is one more good sign.
And a five-second bonus test, when I have a doubt about a piece with no visible hallmark: the magnet. Gold isn't magnetic. If your piece sticks to a magnet, it's not solid gold — full stop. The reverse isn't proof (many non-precious metals aren't magnetic either), but it's a quick knockout that unmasks plenty of fakes.
And when the hallmark is illegible, worn, or the piece comes from a private seller with no guarantee? You don't guess, you have it checked. For €5 to 10, buy-back chains like Easy Cash or Cashfaire authenticate a piece and tell you whether it's gold or not. A jeweller can do it too. It's trivial next to the price of a piece, and it spares you years of keeping something you're not even sure about.
Why I still prefer official shops
I'll be honest: I've bought gold from private sellers, on Vinted, in that relationship of trust where you have to take the other person at their word. And to this day, some of those pieces I almost don't dare have certified — for fear of discovering I got fooled. I know I've only ever sold the real thing. But the reverse, on what I bought C2C, I can't guarantee.
That's precisely why on OrOGramme I only list official shops, with a physical location, that certify their pieces. The hallmark is your own check, your last-minute safeguard. But real comfort is buying where the question doesn't even come up.
French second-hand 18-carat gold shops, certified, normalised per gram and sorted by the best deal on the metal.
To wrap up
The hallmark isn't a specialist's detail: it's the one thing that separates a heritage piece from a decorative one. Learn to recognise the eagle head and the owl head, beware of "GP" and "gold plated", and when you hesitate, drop €5 to know for sure.
I'm telling you what I do, in my own words and from my experience as a buyer. Apply it to your own situation — but start by turning over the next piece you look at, and search for the little creature.
Sources for the figures cited:
- Eagle-head hallmark (750 gold / 18-carat) and the French guarantee system: made-in-joaillerie.fr, accessed 3 June 2026
- Gold hallmark correspondence (shell 585, clover 375) and guarantee symbols: abacor.fr, accessed 3 June 2026
- Owl-head hallmark (second-hand gold / foreign or undetermined origin, ≥ 750 thousandths): bijoux-or-occasion.fr, accessed 3 June 2026
- Lozenge maker's mark (mandatory signature of the French manufacturer): piecesdemonnaie.net, accessed 3 June 2026
- €5–10 authentication price at buy-back shops: Sara's testimony (voice note 10, 28/05/2026), to be reconfirmed