A replica Cartier Tank Must sold as gold is, in most cases, a steel case with gold plating or a PVD coating. Solid 18k gold cases exist in the replica market at higher prices and with different weight. The genuine line uses two gold formats: 18k gold on current references, and vermeil, which is gold over sterling silver, on the original 1970s Tank Must. Plating on replicas often measures under 3 microns. It rubs off at case edges, lugs, and the crown within months of daily wear.
What the genuine Tank Must is
Cartier launched the Tank Must de Cartier in 1977 as a lower-cost Tank. Cases were vermeil, with colored lacquer dials in burgundy, blue, and black. Cartier brought the name back in 2021 with steel cases, quartz movements, and a metal bracelet option. Case sizes run 33.7 mm by 25.5 mm for the Large and 29.5 mm by 22 mm for the Small. Gold versions in the current line use 18k yellow gold or 18k rose gold.
Plating, vermeil, and solid gold
- Vermeil: French law requires at least 5 microns of gold over silver of 800/1000 fineness or higher.
- Plated steel: a steel core with a gold layer. Thickness varies. No minimum standard applies.
- Solid 18k gold: 750 parts gold per 1000. Density near 15.5 g/cm3 against 7.9 g/cm3 for steel.
A solid gold Tank Must case weighs about twice a steel case of the same size. A plated case matches the steel weight.
Checks that take a minute
- Look for a fineness stamp. 18k gold carries "750" or "18k". French assay offices use the eagle head mark for 18k.
- Weigh the watch. Compare against the steel version of the same size.
- Test with a magnet. Gold is not ferromagnetic. Many steel cases pull a magnet.
- Check wear points. Plating fails at sharp edges and the crown before it fails on flat surfaces.
- Open the caseback and read the movement. Quartz and mechanical parts differ in shape and finish.
Movement claims
Cartier fits quartz movements to some Tank Must references and mechanical movements to others. Replica listings mix the two. A listing that says "Swiss movement" without a caliber number gives no verifiable data. Replicas have no service network and no parts supply. A failed movement means a new watch.
Legal status in the United States
A watch that carries the Cartier name without Cartier's authorization is a counterfeit, not a replica. Importing counterfeit goods into the United States is prohibited. U.S. Customs and Border Protection can seize the shipment and destroy it. Trafficking in counterfeit goods carries criminal penalties under 18 U.S.C. 2320. Resale of a counterfeit as genuine is trademark infringement and fraud.
Facts that stay unknown
Replica sellers do not publish gold purity, plating thickness, or movement origin. No independent lab data exists for most listings. Weight and hallmark checks give the most reliable read.