The short answer
A fake Cartier gold piece is a base metal part with a gold coating. The base is brass, steel, copper, or silver. The coating is a few microns of gold, or a gold-colored alloy. Real Cartier gold jewelry is 18k, stamped 750. Real Cartier gold watch cases are 18k. Four checks expose most fakes: the hallmark set, the density, the weight against melt value, and the finish under 10x magnification.
1. Know which Cartier gold you are looking at
Cartier sells three different things that buyers call gold.
- 18k solid gold. Jewelry and watch cases. Marked 750, 18K, or Au750. 75% fine gold by weight.
- Vermeil. The Must de Cartier line from the 1970s and 1980s used 925 sterling silver with a heavy gold plate. Casebacks carry silver marks, not gold marks. Listings call these gold. They are silver.
- Gold plating on base metal. Common on counterfeit Love bracelets, Juste un Clou, and Santos cases. No gold content that counts. Plating thickness in most samples runs 0.5 to 3 microns.
2. Read the hallmarks as a set
One stamp proves nothing. Fakes copy the 750 stamp with a laser engraver. Look for a full set that matches the piece and its market.
counterfeit cartier gold watch
- French-made pieces: eagle head mark for 18k, a maker's mark in a lozenge, and the Cartier signature.
- Swiss-made watch cases: St. Bernard head mark for 18k, plus 750, plus the case reference and serial.
- US-market pieces: 750 or 18K plus the Cartier stamp. US rules for gold markings sit in 16 CFR Part 23.
- Serial and reference numbers must match the model, the year, and the metal. Cartier engraves these. Fakes stamp or laser them.
Look at the stamps at 10x. Real hallmarks are struck. The metal around the mark moves. Laser marks sit flat, with sharp edges and no raised metal.
3. Weigh it and do the melt math
Gold price moves. The formula does not. Weight in grams x 0.75 x spot price per gram = melt value of an 18k piece.
A size 17 Cartier Love bracelet in 18k gold weighs about 30 g to 34 g. A plated brass copy of the same size often weighs 18 g to 24 g. A tungsten copy can weigh more than the real piece.
If a new solid gold Love bracelet is offered at $900 and melt value is $1,700, the metal is not 18k gold. No reseller takes a 45% loss on a metal with a public price.
4. Check density, not magnetism
The magnet test proves little. Brass, copper, and 316L steel are not magnetic either.
- 18k yellow gold: about 15.5 g/cm3
- Fine gold: 19.3 g/cm3
- Tungsten alloy: about 18 g/cm3 to 19 g/cm3
- Brass: about 8.5 g/cm3
- 316L steel: about 8.0 g/cm3
A water displacement test with a 0.01 g scale separates brass and steel from gold. It does not separate tungsten from gold. For that you need XRF or a fire assay.
XRF reads the surface. A thick gold plate over brass can read as gold on a handheld unit set to jewelry mode. Ask for a reading on a filed spot, or ask for a specific gravity result.
5. Inspect the finish
- Love bracelet screws: real screws turn with one screwdriver and sit flush. Fakes use screws that are cosmetic, or that sit proud of the surface.
- Edges: plating wears first at the inner edge and the screw slots. Real gold shows a scratch, not a color change.
- Engraving depth: Cartier cuts the inner band at a constant depth with a clean baseline. Fake engraving is shallow and uneven.
- Joints: cast fakes show a seam at the hinge or the clasp.
6. Gold Cartier watches
Santos, Ballon Bleu, and Tank models come in 18k yellow, rose, and white gold. The caseback carries the metal mark, the reference, and the serial. A gold case weighs more than a steel case of the same model. A plated steel case shows brass color at the lugs and the caseback threads. Tungsten-core fakes pass a weight check and fail a density check.
7. Legal status in the US
Selling a counterfeit mark in the US is a federal crime under 18 U.S.C. 2320. Customs and Border Protection seizes counterfeit jewelry and watches at ports of entry. A personal purchase is not the same charge, but the item has no resale value and no warranty.
8. If you already bought one
Get a written return policy before you pay. Pay with a card, not a transfer. Ask a jeweler for an XRF reading and keep the printout. If the listing used the word gold and the item is plated, a chargeback claim has grounds.