Fine Jewelry Authentication Specialist
Fine jewelry authentication specialist. Focuses on hallmarks, stone setting, and metal finishing.
Published November 2026 · Contact
What a Genuine Juste un Clou Looks Like
The Juste un Clou is Cartier's nail bracelet: a thin gold bangle that is bent into a single wrap so that one end is a nail head and the other a sharp point. It is made in yellow, rose and white gold, plain or with diamonds set in the nail head and the tip, and in several widths. It is resold constantly, and because it has no screws, no clasp and almost no lettering on show, buyers are left with very little to check. That is why "is my Juste un Clou real" is a common question.
Almost everything there is to check is on the inside of the band: one engraved line, a hallmark and, if you have it, the certificate. This guide goes through them on genuine bracelets in three golds.
Worth knowing
This is a genuine reference guide. The bracelets it describes passed authentication. We do not have enough counterfeit Juste un Clou bracelets, of the same size and metal, to publish a list of fake tells we would stand behind, so there are no red-flag checks below. If that changes, this guide will be upgraded. The engraving and the nail head vary with the size, the metal and the year, so compare with a bracelet of the same kind.
Use our free Cartier Serial Checker to check the engraved serial against the formats Cartier is documented to use.
Check My Serial →The Shape: Nail Head, Grooved Shank, Tapered Point
On the genuine bracelets we have seen, the nail head is a short round disc with a flat face. Behind it the shank carries a run of small raised grooves, like the thread of a nail, and the other end tapers to a point that overlaps the shank. On the diamond versions a band of small diamonds is set round the edge of the head, and a small diamond-set strip runs along the point.
On a diamond bracelet look at the setting rather than the sparkle. The stones along the head sit in an even row, the same size, with the metal between them kept thin and level. Uneven spacing, stones that sit proud or a band that tilts on the head are reasons to compare more carefully. A tidy setting does not prove a bracelet, since a good fake can set stones neatly, but a messy one on a bracelet that should be finished like jewellery is hard to explain.
The Engraved Line
All the genuine bracelets we have seen carry the same line on the inside of the band, close to the nail head, in small fine characters:
- the script © Cartier,
- a two-figure size, for example 15 or 17,
- a serial of three letters and three digits, for example OTJ526, IZE188 or YME069,
- Au 750, the 18-carat gold mark,
- and, after it, a small rectangular hallmark next to further small stamps.
The characters are evenly cut and evenly spaced, the "Cartier" script is a fine slanted hand, and the line follows the curve of the band without drifting. On the yellow gold bracelet there are further small stamps beyond the first hallmark, so a second set of marks near the nail head is normal. Expect the marks to be small: on a plain bangle they are about the height of a pinhead.
Do not treat the format as the check. A serial of three letters and three digits is easy to copy, and an engraving with the right layout is exactly what a careful counterfeit would show. What is worth comparing is the cutting: depth, spacing and the shape of the script, against a genuine one of the same metal.
The Serial and the Certificate
The serial on the band is repeated on the certificate. On the yellow gold set the certificate is a small red-covered booklet headed CERTIFICAT / CERTIFICATE, with the serial written by hand, a date, a stamp and a signature, and the serial it gives matches the engraved line. On the white gold set the certificate is the same booklet, with a printed number at the bottom.
Check that the serial written on the certificate is the serial engraved on the band, and that the size matches. A matching pair is what you expect from a genuine bracelet bought new. It is not proof on its own: certificates and boxes can be bought or copied, and a real certificate can sit with a different bracelet. Treat it as one more mark to compare, never as the answer.
The Packaging
A new bracelet comes in a red Cartier box with the gold Cartier script on the lid, a red velvet pouch with two press studs, a shopping bag in the same red and a cleaning cloth. The box is covered in a fine cross-hatched textured paper, and the script is a clean, thin gold foil impression.
Packaging is the easiest part of a set to buy separately, so it tells you the least. Use it to check the script and the paper, not to decide the bracelet.
What a Matching Mark Does and Does Not Prove
A matching engraving, a hallmark and a certificate with the same serial are what a genuine Juste un Clou shows. Fakes copy every one of those, including the layout of the line, so a match proves nothing on its own. In our own review of a counterfeit diamond Juste un Clou the engraved line carried the same elements as the genuine ones: the Cartier script, a size, a serial of three letters and three digits and Au 750. The difference was in how it was cut, which one bracelet is not enough to turn into a rule.
Weight, the feel of the shank and the way the bangle springs back are checks done with the bracelet in your hand, and they depend on the size and the metal. The checks that carry the most are the cutting of the engraving, the finish of the nail head and the setting of the stones, compared with a verified bracelet of the same kind.
When to Get a Professional Opinion
If you are paying for a bracelet that costs several thousand dollars, or the serial, the hallmark or the setting looks wrong to you, have it reviewed against verified examples of the same metal and size before you buy. You can get a Cartier piece checked from photos of the engraved line, the nail head, the tip and the certificate. If you also own a Love bracelet, our Cartier Love bracelet guide covers its marks, and the Cartier serial number guide explains what a Cartier serial can and cannot tell you.
FAQ
How can you tell if a Cartier Juste un Clou is real?
Start with the engraved line inside the band: the Cartier script, a two-figure size, a serial of three letters and three digits, Au 750 and a small hallmark, all evenly cut. Then compare the serial with the certificate, and look at the finish of the nail head and the setting of any stones. No single mark settles it, because fakes copy the layout.
Where is the serial number on a Juste un Clou?
On the inside of the band, close to the nail head, in the same line as the Cartier script and the gold mark.
Can you authenticate a Juste un Clou from photos alone?
Yes. What decides it is the engraving, the hallmark, the nail head and the setting, so clear photos of those, plus the certificate, are what to send.
Does a certificate prove the bracelet is real?
No. The serial on the certificate should match the one on the band, but certificates and boxes can be separated from the bracelet or copied, so a match is one mark among several.
Do you have a list of fake Juste un Clou tells?
Not yet. We do not have enough confirmed counterfeit bracelets of the same size and metal to publish a list we would stand behind, so this guide shows genuine bracelets only.
