Quick Answer
The Cartier Tank Must is a quartz watch, so any listing that advertises a Swiss automatic movement inside a "Tank Must" is describing a copy, not the real thing. From there, the fastest checks are the crown cabochon, the sharpness of the dial printing, and the hidden Cartier signature worked into one of the Roman numerals.
Which Black Tank Must You Are Looking At
Two different watches share the name. The modern Tank Must, relaunched in 2021, uses a steel case, a quartz caliber, and colored lacquer dials. The vintage Must de Cartier Tank from the 1970s and 1980s used vermeil cases, which are sterling silver with heavy gold plating, and came with black or bordeaux lacquer dials. Knowing which family you are holding changes every check that follows, because the case metal, the movement, and the markings are not the same.
Step-by-Step Checks
- Confirm the size. A modern Tank Must Large measures roughly 33.7 mm by 25.5 mm. Ask for caliper photos instead of trusting a listing image.
- Verify the movement. Genuine modern Tank Must runs on quartz, with battery life quoted in years. A seller praising an automatic movement inside a steel Tank Must is selling something else.
- Inspect the crown. Real cabochons are faceted sapphire or spinel with sharp edges and deep color. Copies use dyed glass or plastic that looks cloudy in raking light.
- Read the dial print. "CARTIER" should sit in even Roman capitals with no bleed at the edges. Look for the hidden Cartier signature worked into the VII or the X numeral.
- Study the lacquer. A black lacquer dial should read flat and glossy across the whole surface, with no orange peel texture and no wavy reflections.
- Check the case finish. Polished and brushed surfaces should meet on a sharp, straight line, with no rounding or soft edges at the lugs.
- Examine the caseback. Reference and serial numbers are laser engraved, not stamped, and the lettering should stay crisp under a loupe.
- Ask for paperwork. Box, warranty card, and service records do not prove authenticity alone, but a seller who cannot produce any of them is a larger risk.
Where Copies Fail Most
Replica dials usually give themselves away at the printing stage. The lacquer is thick, the text is slightly heavy, and the numeral strokes lose the tapered look of the original. Crowns are the second weak point, since a convincing faceted cabochon costs more than most replica makers want to spend. Caseback engraving rounds out the list, because stamped serials sit shallow and fill with grime over time.
Vintage Must de Cartier Notes
On a 1980s Must de Cartier, check the vermeil hallmark and the plating wear at the lugs, where honest age shows as thin gold over silver. A black lacquer dial on these watches should carry the "Must de Cartier" script in proportion to the case, not stretched or crowded toward the edge. Have any vintage piece opened by a watchmaker before you pay, since movement swaps are common in this era.