A fake A. Lange & Sohne platinum watch is a watch whose case is not made of PT950. Most copies use steel with rhodium plating, 18k white gold, or a tungsten heavy alloy. Three checks settle the question: the caseback stamp, the weight on a scale, and the movement under the sapphire back.
What PT950 Means on a Lange Case
A. Lange & Sohne stamps platinum cases PT950. That is 950 parts platinum per 1,000, or 95 percent by weight. Swiss assay law requires a fineness stamp on precious metal cases. United States rules from the Federal Trade Commission set the same threshold. A product marked platinum with no qualifier must be at least 950 parts per thousand. Alloys between 850 and 950 carry the number, for example 850 Plat.
On a Lange case, look for PT950 inside the caseback, next to the case number and the reference number. Some references carry a second stamp on the case side between the lugs.
Weight Is the First Filter
Platinum has a density of 21.4 g/cm3. White gold at 18k fineness runs about 15.5 g/cm3. A platinum Lange 1 head weighs about a third more than the same case in white gold. Pick the watch up and the difference is clear.
Weight alone does not prove platinum. Tungsten heavy alloys reach 18.5 g/cm3, which is heavier than gold. A heavy fake is not a platinum watch. Weigh the head on a calibrated gram scale and compare the result against the published case size for that reference. Lange publishes diameter and thickness for each model.
Caseback Engraving
- Genuine: cut engraving with sharp edges under 10x magnification. The text reads A. Lange & Sohne, Glashutte i/SA, Made in Germany, PT950, plus the reference number and the movement number.
- Fake: laser etching that reads gray and flat, wrong letterforms, spacing that drifts, or metal terms such as Platin and Platinum 950 that Lange does not use.
The Movement
Lange builds its movements in Glashutte. Signs of a real one: a three-quarter plate in untreated German silver, screwed gold chatons, blued screws, a hand-engraved balance cock, and a swan-neck regulator. The Lange 1 and the Datograph are hand-wound. An automatic rotor under the back of either reference points to a fake.
Copies use ETA 2824 clones, Seagull calibers, or Miyota calibers with decorative plates. The balance cock engraving is the tell. Lange cuts it by hand, so no two are the same. Fakes repeat one stamp on every unit.
Dial and Date
The Lange 1 outsize date uses two discs, one digit each. The tens disc jumps at the end of the month, the units disc advances each day. Copies use a single disc with printed digits, or a pair of discs that do not snap into place. Dial print is another marker. Lange print is thin. Fake print is thick, and the model name fonts differ from the original.
Papers, Box, and Price
Lange ships a wood box with leather trim, a guarantee booklet, and a serial number that matches the case. A mismatched serial is a warning sign. Lange does not sell new watches through general retail channels. New stock moves through boutiques and authorized dealers.
Price is a filter. A used platinum Lange 1 trades above the white gold version of the same reference. A platinum-marked Lange offered at white gold money does not contain platinum.
Verification Steps
- Open the caseback at a watchmaker and read the stamps.
- Weigh the head on a calibrated scale.
- Record the movement number and send it to A. Lange & Sohne in Glashutte. The company keeps production records and answers authentication requests.
- Compare the reference number against Lange catalog data for case metal and dial type.
Platinum is sold at a premium over white gold, so fakes target platinum references for the price gap. A fake that passes a visual check still fails the scale and the engraving.