Short answer
A replica Cartier Tank Must in gold is a quartz watch with a gold-plated, gold-capped or solid gold case. The large model measures 33.7 mm by 25.5 mm. The genuine Tank Must uses a quartz movement, so a replica quartz copies the function. Most watches sold as "gold" use plating, not 18K gold.
What the genuine Tank Must is
Cartier launched the Tank Must in 2021 as the replacement for the Tank Solo. The Tank line dates to 1917. Cartier lists steel and 18K yellow gold versions. The large case is 33.7 mm by 25.5 mm. The small case is about 29.5 mm by 22 mm. Both stay under 7 mm thick, which is why the model slips under a cuff. Cartier fits quartz movements to the line, including a SolarBeat version with a photovoltaic dial under the Roman numerals.
An 18K gold case is 75 percent gold by weight. A 30 g case holds about 22.5 g of pure gold, near 0.72 troy ounces. The spot price changes each day. At $2,400 per ounce, that metal alone costs about $1,700. This number sets the floor for any honest solid gold build.
Gold finishes in the replica market
- Gold plating: 0.5 to 5 microns over brass or steel. Wear shows first at the crown, lugs and caseback rim.
- PVD coating: a titanium nitride or gold-tone layer. Color holds longer than plating. The tone reads bronze or orange next to 18K yellow gold.
- Gold cap: a bonded sheet of gold alloy over a base case, often 40 to 200 microns.
- Solid 18K: a milled gold case. Few replica sellers offer it, because the metal cost is high.
Checks before you buy
- Weight. A plated brass case feels light for a 33.7 mm watch. A solid gold case has heft.
- Hallmarks. Cartier gold cases carry assay marks and the reference number. Replicas often show a stamped 750 with no assay punch.
- Caseback engraving. Compare depth, font and spacing against photos of the real reference.
- Movement. The real watch runs a Cartier quartz calibre. Many replicas run Ronda, Miyota or unbranded Chinese quartz.
- Strap and buckle. The genuine gold model pairs a gold ardillon buckle with an alligator strap.
Care
Plating fades with sweat, perfume and strap rub. A soft cloth and fresh water slow the wear. Plated metal cannot be polished back to gold. Replating costs less than a new case, but the color match varies by shop.
Unknowns
Replica sellers do not publish plating thickness, case metal or movement grade. Two watches from one listing can differ. No public factory list exists, so claims of "1:1 gold" or "Swiss made" cannot be checked from a photo.