Answer first
Most watches sold as a fake Ballon Bleu in white gold are steel replicas with rhodium plating, not 18k gold. The dial, the cabochon and the box prove nothing. The case metal decides the price, so check the hallmarks, the weight and an XRF reading before money changes hands. If the seller cannot name the reference number and accept a return, walk away.
Prerequisites
- A 10x loupe and a bright desk lamp
- A scale that reads to 0.1 g
- Vernier calipers
- The exact Cartier reference number for the white gold model you want
- Access to a jeweler with an XRF tester
Step by step
- Write down the reference number, case diameter, case thickness and bracelet type for the white gold Ballon Bleu you are comparing against.
- Weigh the watch head on the 0.1 g scale and record the number next to a steel version of the same size.
- Measure the case diameter and thickness with the calipers and compare both numbers to the reference data.
- Examine the caseback and the area between the lugs with the loupe for the 750 stamp, the Cartier maker's mark and a Swiss assay mark.
- Look at the crown cabochon under the lamp: synthetic spinel sits in a gold crown, and a glued plastic dome with a visible seam is a replica part.
- Read the dial printing at 10x. Genuine text has crisp edges and even spacing; plated replicas show ink spread and uneven Roman numerals.
- Ask for clear photos of the movement, including the rotor and the balance, then compare the finish with a known example.
- Check the clasp stamping and the end link fit, since plated replicas often show soft edges and a loose bracelet.
- Have the case tested with XRF inside the return window and keep the written result.
White gold versus plated steel
18k white gold is a dense alloy and a Ballon Bleu case in that metal carries a weight that steel cannot match at the same dimensions. Rhodium plating looks correct on a photo and gives the same pale tone, so color is not evidence. The hallmarks and the assay mark are struck into the metal and survive polishing; plating covers them or leaves them shallow and blurred. A jeweler's XRF test reads the surface alloy in seconds and settles the question.
What replica white gold usually means
Sellers use the phrase to describe a steel case with a white metal finish, sometimes with a gold cap on the bezel. Ask which parts are solid gold and which are plated, and get the answer in writing. A listing that avoids the words steel, plated or solid gold is telling you the answer already.
Price and paperwork checks
Solid white gold carries a metal value that sits far above any replica price, and that gap is the clearest signal in the listing. Ask for the original Cartier certificate, the service history and the seller's return terms in one message. Compare the serial number on the caseback with the paperwork, and confirm the return window covers a full day with a jeweler.