Quick answer
A counterfeit Must de Cartier fails on four checks. The caseback engraving is shallow or stamped instead of cut. The vermeil hallmark is missing, wrong, or in the wrong place. The crown cabochon is glass, not synthetic spinel. The watch weighs less than a genuine example of the same reference. Genuine Must de Cartier cases from the 1970s and 1980s carry deep engraving with a raised lip at the end of each stroke, and vermeil cases carry a Swiss silver hallmark in addition to the Cartier name.
What the Must de Cartier line is
Cartier launched the Must line in 1973 as a lower-priced entry into the brand. Most pieces used vermeil, which is sterling silver with a heavy gold plate, plus quartz movements and a cabochon crown. The line sold in large numbers and stayed in production for decades. That volume is the problem for buyers today. There are far more fakes than genuine examples on the secondhand market, and the fakes have had forty years to improve.
Before you start
- 10x jeweler's loupe
- Raking light, such as a desk lamp held at a low angle
- Kitchen scale that reads to 0.1 g
- Reference photos of a genuine example in the same size and metal
Inspection sequence
- Weigh the watch with the strap removed and write the number down.
- Set the watch under raking light and photograph the caseback at 3x zoom.
- Read the engraving through the loupe and check stroke depth and letterforms.
- Look for the metal hallmark: a walking bear for Swiss silver, or a maker's mark beside it.
- Inspect the crown cabochon for bubbles, seams, and a plastic-looking surface.
- Compare the dial text to your reference photo, letter by letter.
- Check the caseback screws or tool marks for damage that suggests a movement swap.
- Ask for a movement photo and compare the caliber stamp to the reference.
Caseback engraving
Genuine Must cases were engraved with a cutting tool. Under a loupe, the grooves show a slight taper and a raised lip at the end of each stroke. Fakes are often stamped or laser-etched. Stamped text has rounded, shallow edges with no lip. Laser etching looks sandy and sits on the surface rather than in it. The most common error is spacing: fake "Must de Cartier" text runs together or spreads out at the end of the line.
Vermeil and metal hallmarks
Vermeil is not solid gold and it is not gold filled. It is sterling silver with at least 2.5 microns of gold, and genuine pieces are marked as such. On a real Must you will find the Cartier name, the reference or model number, and a Swiss or French silver hallmark. Fakes often show "925" alone, or a hallmark in the wrong shape, or no hallmark at all. A gold-plated base metal case shows wear as gray or pink patches where the plate has rubbed through, not as silver.
Crown and cabochon
Genuine cabochons are synthetic spinel or sapphire. They read as a deep, even blue and they feel smooth and cool. Glass or plastic cabochons show air bubbles, mold seams, and a lighter, flatter blue. Check the setting as well. On a genuine crown the stone sits flush inside a clean bezel, while fakes often sit high with visible glue.
Dial and hands
Dial printing on a genuine Must is crisp with tight serifs and even baseline spacing. Fakes show thickened strokes, fuzzy edges, and a Roman numeral that leans or sits uneven. Hands should match the reference shape, with even lume or no lume depending on the model. Check dial feet positions if the movement is visible. Swapped dials are a frequent issue on vintage pieces.
Serial numbers and paperwork
Serial numbers help, but they do not prove a watch is genuine on their own. Fake sellers copy real serials from photos. Use the serial to check the model and the production era, then fall back on the physical checks above. Papers and boxes are easy to print today, so treat them as a bonus and not as evidence. A service record from Cartier is stronger than any card.
Price signals
A genuine vermeil Must Tank in working order sells for a few hundred to low four figures in US dollars, depending on size and condition. A listing far below that range is a fake or a parts watch. A listing inside the normal range can still be a fake, so run the checks before you pay.