It seems there is a lot of mystery surrounding this innovation made by Rolex so I will try and clear it up using two documents of pretty good authority. I wish I could say I had talked to the head of the parachrom department at Rolex but I haven’t.

The parachrom hairspring didn’t really start getting attention until a couple of years ago when it started appearing in the new GMT-Master II. It’s distinctive blue color meant that Rolex had to spill the beans about what they had done. I first heard about it when a Rolex representative taught me about it in early 2007.

James Dowling (Mr. Rolex) of timezone wrote a nice article about the Parachrom Blu hairspring in August of 2007. — John B. Holbrook, II of the Rolex Reference Page refutes Mr. Dowling’s claim that the parachrom blu hairspring was fitted to all Daytona’s featuring the 4130 movement in his article The Evolution of the Modern Era Rolex Daytona. I am going to take a middle ground.

The following is from a Rolex communication titled Parachrom Hairspring dated 08/12/06 given to representatives at a factory tour in Geneva:

ROLEX has developed and patented a new hairspring called PARACHROM. This hairspring is made of a niobium, zirconium and oxygen alloy. It has been used for the Cosmograph Daytona starting from 2000.

In 2005 a blue-coloured version was introduced for the new GMT Master II and the Cosmograph Daytona. It has an even better performance as regards to long-term stability. This blue version has also been patented.

The hairspring and balance form an oscillator, the regulating organ of the watch. This oscillator is the guardian of time. The precision of the watch is determined by the regularity of its oscillations. The requirements of this regularity are very great since measuring the time with a precision of 1 second per d ay is like measuring a distance of 1 km to within 1 cm.

To guarantee this extreme precision, the torque must be as constant as possible regardless of the temperature to which the watch is submitted. It is for this reason that only a few, very special materials can be used for the hairspring.

Commonly used alloys have an iron - nickel - chromium base. These alloys are ferromagnetic and so have two major drawbacks: they make the hairspring susceptible to magnetic fields and to shocks.

ROLEX has developed a new family of alloys with a niobium - zirconium - oxygen base know as PARACHROM, which is up to ten times less susceptible to shocks and absolutely unaffected by magnetic fields.

The registered name comes form the fact that the alloy is paramagnetic and that it is coloured (CHROM in Greek).

This development required 5 years of research by physicists and materials engineers and called for the most advanced observation and analysis techniques. It resulted in the filing of applications for two patents, one for the protection of the chemical composition of the alloy, the other the way of modifying the surface of the hairspring to stabilize its properties (blue colouring). The blue colour of the hairspring increase the prestige of the watch. As a matter of fact, in the history of watch making, bluing a hairspring was an operation done only for the most accurate and sophisticated watches.

If the material of the PARACHROM hairspring is very specific, its manufacture necessitates very high technology which is fully mastered in house.

. . .

In 2005, ROLEX introduced another new feature on the PARACHROM hairspring by modifying the structure of its surface. The layer of oxygen present on the surface is transformed and thickened to about 50-100 nm to increase the long term stability of the oscillator even further. This modification of the surface colours the hairspring in blue (colouring by interference). This innovation has been patented.

The hairspring shown in Mr. Holbrook’s article which he says, clearly “is not a Parachrom Bleu but rather a standard Nivarox hairspring” is in fact a Parachrom hairspring from before the color innovation of 2005.

You can see a short video from Rolex on the parachrom hairspring at their web page.

The parachrom hairspring has been fitted into:

• All Daytona’s since 2000 (4130 caliber).
• New versions of the GMT Master II (released in Gold 2005, Rolesor 2006, Steel 2007
• Milgauss (2007)
• Deep Sea Sea Dweller (2008)
• Day Date II (2008)
• Gold Submariner with ceramic bezel (2008)

It will eventually be fitted into all models (apparently as they get redesigned) as production allows.

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