The image of the scales of justice is iconic in its own right. The symbol itself comes from both Greek and Roman mythology and the tale of Themis and Justitia. Themis was the Greek goddess of justice and law, known for her ability to see into the future and her clarity of mind. Justitia, on the other hand, was the Roman goddess of justice, symbolized wearing a blindfold and holding the evenly balanced scales. Taking things one step further, the scales themselves are actually derived from Egyptian mythology and the goddess Maat.
Why go down this historical rabbit hole? Well, for one – in a previous life – I worked in law, and I am automatically drawn to things like this. Secondly, it occurred to me recently – while writing an article on the new Oyster Perpetual 34 – that Rolex is developing two distinctly different balance spring and escapement technologies side by side. Both represent advancements in accuracy and technological watchmaking. Above all, they represent the use of materials which are highly amagnetic. The thing I was left wondering is, why not just pursue one technology? Much like Themis, I have to think Rolex can see what the future holds for both movement types. On the other hand, what – above all else – can throw off the balance of a watch? Magnets (not even Justicia can help). But why two different amagnetic watchmaking methods? So many questions.
Now, Rolex has, for some time, been proceeding down this dual balance spring and escapement road, when it at one point seemed as if they were going all-in on one of them. This became more evident with the release of the Oyster Perpetual models in both 36 and 41mm which both feature movements fitted with the Rolex Chronergy escapement and Parachrom bleu balance spring. More than that, the OP collection of watches alone is bifurcated between two movement technologies. Considering the fact that I am not privy to the inner workings of Rolex, I think it is worth digging into the history of alternative watchmaking materials, and the benefits of both a silicon and Parachrom balance spring.
In light of this endeavor, this seems as good a time as any to dig a bit deeper into the balance spring in general. Essentially, the balance spring, within the movement of a watch, is a small spiraling coil that is attached – and provides restoring forces – to the balance wheel, allowing it to oscillate. Historically speaking, a balance spring was fashioned from steel (or, more rarely, materials like gold or even glass), but modern innovations have seen the introduction of more temperature resistant alloys, or metalloids, such as Parachrom and Syloxi.
Innovation, mind you, doesn’t normally take place for the sake of innovating. There has to be a reason – or, rather, a problem which must be solved. In the case of watchmaking, public enemy number one seems to be the magnet. I am not talking about that fridge magnet you picked up in Colonial Williamsburg and stuck haphazardly on your refrigerator door. The issue is with high-powered magnets, rare magnets, and the kind of magnets that we don’t come into contact with regularly. Magnets present a great risk, and the effect on a watch can be devastating to its accuracy. Nobody wants a magnetized watch. This is precisely the reason why such advancements in movement materials have been underway for the past 30 or so years. Magnetism is inevitable, but new materials such as silicon and niobium-zirconium show that watches can endure.
There are a variety of ways in which the movement of a watch can be constructed in order to withstand the dangers of magnetism, and the advent of modern technological material breakthroughs is just one of them. To this point, watchmaking has seen two approaches: Hide the movement behind a wall, or take magnetism head-on through the innovative use of materials.
As I will get into shortly, Rolex’s Parachrom balance spring is fashioned from two elements – one of which is niobium (a highly amagnetic material). But Rolex was not the first brand to use such a material. In 1989, IWC introduced possibly the earliest example with the Ingenieur 500,000 A/m (amperes per meter, one of several units for magnetic fields). This 34mm watch used, in its movement, niobium-based alloys which produced a watch capable of withstanding intense magnetic fields without the need for a soft iron inner cage (a conductor of magnetic fields which will not stay magnetized, thus protecting the movement). The Ingenieur 500,000 A/m did not last long. IWC produced it for roughly one year and sold about 3,000 units. Instead of continuing to produce movements of this kind, IWC has reverted back to the use of the soft iron inner cage, especially in its Pilot watch line.
It is worth noting that a soft iron cage is not the same as a Faraday cage, which is designed to protect electronic equipment from external radio frequency interference. Back in my days in the legal profession, I had a chance to work in the world of IP and patent law. As you well know from watches, patent disputes can be very contentious. I had the opportunity to observe engineers and computer scientists building a Faraday cage in order to power a piece of electronics without it receiving any cellular or radio data in the process. That non-sequitur notwithstanding, the point remains that soft iron cages are responsible for protecting a watch movement from a magnetic field, as opposed to a Faraday cage.
Rolex utilizes what it calls a soft iron shield to protect the movement inside of the Milgauss – despite the fact that the movement itself is made of amagnetic material for the balance spring, escape wheel, and lever. If you were to remove to caseback of the watch, you would not see the movement, but rather, that very shield marked with the letter B. This soft iron shield is likely a Mu metal. A Mu metal alloy provides an alternate route for magnetic fields, causing them to flow around a movement through an enclosure, as opposed to the steel parts of the movement itself. Just like Themis and the scales of justice, “Mu metal” is derived from the Greek letter Mu, which is the symbol for magnetic permeability. For more on Mu metals and all things magnetic, check out Jack’s In-Depth from a few years back.
Many watches use something called Nivarox alloys for their balance springs. Generally speaking, a Nivarox alloy is quite resistant to magnetism, but in the event that the movement does pick up a magnetic field, the next thing to worry about is temperature compensation. One of the indicators of a magnetized watch is that it runs fast. A watch with Nivarox components that becomes magnetized will have additional timing issues associated with temperature, in that the watch will run at different intervals (fast or slow) depending on a particular change in temperature.
The pursuit of antimagnetic materials has surpassed the point of shielding the movement from magnets. As was the intention of the Ingenieur 30 years ago, the imperative now is to create parts that can withstand magnetism outright, without a cage or a shield. Not long ago, Omega introduced the Si14 silicon balance spring to combat many of the issues that can be had when a watch picks up a magnetic field. Omega was able to create, with the Si14, a much easier method of crafting the balance spring itself. When working with metals, it very difficult to shape a balance spring – I mean, it is a thin coil after all. The silicon balance spring, on the other hand, and specifically the Si14, is able to be printed to exacting details from large silicon discs.
Omega and Rolex are leading the charge in terms of pushing the boundaries of watchmaking technology and materials. So what happened to IWC, and the Ingenieur and its impressively resistant niobium movement technology? Well, it was an extremely expensive endeavor to create the movements, and the volume of watches it took to justify the continuing production with the low sales numbers was untenable and not a price IWC could swallow at the time, and likely would be difficult today. Needless to say, IWC moved on from it, but its place in history remains. In fact, Rolex, in a lot of ways, used the advancements of IWC as a jumping-off point for its Parachrom balance spring.
Sometimes, Rolex likes to do things that are a technical challenge purely for the sport of it. The creation of the Parachrom amagnetic balance spring certainly was that. In addition, Rolex doesn’t work within the same financial constraints as other watch brands. This results in a unique ability to spend a lot of money – and time – on R&D in order to push the envelope of watchmaking. While I cannot say this for certain, it is possible that Rolex saw the inherent value of what IWC was doing and knew it had the wherewithal (resources, time, funds) to do it itself. Between Parachrom and Syloxi, Rolex set out on a path – unbeknownst to most – toward two distinct types of amagnetic, temperature resistant movement materials.
The Parachrom Bleu Balance Spring
In 2000, Rolex entered the new world of modern watchmaking. In the Rolex Daytona, it introduced the in-house 4130 movement, featuring the first Parachrom Bleu balance spring. This was significant for two reasons. First, and arguably the more important at the time, was the fact that this was the first Rolex in-house caliber for the Daytona (previous renditions used Rolex-modified Zenith movements). This resulted in minor changes to the watch, including a repositioning of the small seconds sub-dial.
The second significance of this release was the aforementioned Parachrom balance spring. This technological and engineering breakthrough from the new millennium is still very much felt to this day. It has since been modified, improved, and paired with more horologically significant advancements (like the Chronergy escapement), but the release of the Parachrom Bleu balance spring marked the arrival of modern Rolex as we know it today.
Rolex spent the better part of five years developing and refining the technology behind the Parachrom Bleu balance spring and has continued to update and perfect it. The technical process required to create it is also quite complex. It involves heating and bonding the two components which comprise it – niobium and zirconium – in a specialized vacuum environment at temperatures near 2400°C. The metals are passed through a furnace multiple times, until they are bonded. When the newly formed Parachrom interacts with oxygen, it turns blue, hence the name bleu. As one would expect, Rolex puts the balance spring through a battery of tests, accounting for even the most minuscule of errors, as they could have a great impact on the accuracy of any given watch. Over time, the Parachrom Bleu has become a central part of modern watchmaking for the brand, contributing to an accuracy of +2/-2 seconds per day (which is the standard, across the board, for all Rolex watches).
The advent of the Parachrom balance spring was Rolex’s answer to the technological breakthrough of the Ingenieur 500,000 a/m. Using similar materials, Rolex created a highly amagnetic balance spring system which would also better combat the aforementioned temperature changes associated with magnetism.
While on the topic of the Parachrom balance spring, it’s worth mentioning Rolex’s other big recent innovation: The Chonergy escapement. Released in 2016, Rolex developed and patented a new escapement geometry, which was a modification of the lever escapement. This new design enabled a 15% increase in accuracy through an overall reduction in mass of the components. Effectively, everything was made lighter. Both the Chronergy escapement and Rolex’s new balance wheel design were essential to the brand’s ability to make its watches more accurate.
Accuracy is not just tied to the amount of seconds gained or lost, but preventing those accuracy readings from deviating too much over time. The Chronergy escapement is made of nickel-phosphorus and is similarly insensitive to magnetic interference, just like Parachrom. Following this pairing of balance spring and escapement, Rolex effectively redefined its own Superlative Chronometer certification, testing every cased watch to an accuracy of +2/-2 seconds per day. That brings things back to the present day, as one of the biggest draws in the new releases this year – the OP 36, 41, and Submariner included – was the fact that Rolex had fitted them each with movements featuring the Chronergy escapement, thereby enhancing magnetic resistance.
The Syloxi Balance Spring
Now, around the same time as the release of the Daytona, and the debut of the 4130 movement (and Parachrom balance spring), Rolex was part of a consortium of brands that researched and developed silicon as a viable option in watchmaking. Not a brand to move quickly on such things, Rolex effectively sat on the technology for years as other brands began rolling out movements with silicon parts. Notably, there was Ulysse Nardin with its landmark watch, the Freak. In later years, the Swatch group would begin rolling out watches with silicon parts – like Omega with the previously mentioned Si14 balance spring. As more brands entered into the silicon-craze – or Sili-Craze – Rolex laid in wait. But as the dust settled, the Crown quietly rolled out its own version of a silicon balance spring.
It is important to note just how long it takes to develop technology of this sort – especially for a brand like Rolex. The release of the Parachrom Bleu in the year 2000 had half a decade of work behind its conception and eventual development. When it came to Syloxi, Rolex spent the better part of 14 years ruminating and gestating over the information gathered by the consortium. 2014 saw the big debut, only it wasn’t very widespread. Rolex was, is, and continues to be very invested in the long-term success of the Parachrom Bleu balance spring (and by the transitive property, the Chronergy escapement). It would likely be a bit jarring if it began rolling out silicon-based movements on a large scale. The watch chosen to carry the silicon mantle was the diamond-encrusted 34mm Rolex Datejust Pearlmaster. The movement inside was the in-house caliber 2236, featuring the Syloxi balance spring. This technology would quickly find its way into a wider range of Rolex women’s watch offerings.
Syloxi (read, silicon or the French silicium) is a metalloid, meaning it may look like a metal, but it is not. It is so named for a Rolex patented silicon geometry allowing for optimized isochronism and enhanced chronometric regularity. The material is a combination of both silicon and silicon oxide, which is how the name Syloxi was derived. As a form of silicon, it boasts amagnetic properties and resistance to shock. The one drawback to silicon, however, is its brittle nature and therefore higher susceptibility to breaking. The Syloxi balance spring contributes to an equally accurate +2/-2 seconds per day as its Parachrom counterpart with the Chronergy escapement.
Given the fact that silicon is very much not a metal, it is effectively undisturbed by magnetism at all. The use of silicon in watch movements is controversial, with many “purists” finding it to be a bit too modern in a world which is very much tied to the classic way of doing things. But you cannot knock its performance and its capability. If you truly wanted to ensure the balance spring would remain unaffected from magnetic fields, silicon would be a great place to start.
The implementation of Syloxi within Rolex was in women’s watches until 2015, with the release of the Rolex Yachtmaster in Everose on Oysterflex. It has the same 2236 movement as the 2014 Pearlmaster. In fact, the one common thread among all the watches containing the 2236 movement is that they are all Oyster Perpetual Date models in some fashion. The 2236 itself is a new version of the 2235 movement which preceded it, both movements with a date function. This brings us to modern-day once again, and the release of the 2232 movement which debuted inside of the new OP 28, 31, and 34 – itself an update over the outgoing 2231. This movement is simply the no-date variant of the 2236, and likewise features a Syloxi balance spring.
Tandem Balance Springs
As a practical matter, both Syloxi and Parachrom are effectively Rolex inventions; Syloxi being a Rolex-patented variation of silicon or silicium, and Parachrom a Rolex proprietary alloy fashioned from niobium and zirconium. Both materials are aimed at protecting the movement against everyday forces inflicted on a watch, which a steel balance spring is vulnerable to by its very nature. As noted, these forces include temperature, shock, and magnetic fields. After all, a balance spring and balance wheel are similar to a pendulum on a clock, except that they are portable and therefore need extra protection against outside disturbances.
One key difference between Parachrom and Syloxi is the composition, or elemental makeup. The two main components of Parachrom – niobium and zirconium – are transitional metals. While Parachrom is amagnetic and may very well boast 10 times more shock resistance than a traditional balance spring, it is still a metal byproduct. Syloxi being a metalloid (and not a metal), it is actually much harder than traditional steel, but can to be fashioned into a spring, or fine coil, all the same. In reality, silicon is more amagnetic than Parachrom, but Parachrom has the added benefit of being paired with the Chronergy escapement to potentially balance the scales.
Rolex is occasionally labeled as both boring and predictable. I look at it a bit differently. I see Rolex as being quite measured and calculating. Just this year, it released a new line of Submariners and Oyster Perpetuals with the new movements featuring the patented Parachrom and Chronergy systems. At the same time, another new Oyster Perpetual was introduced with a new movement and Syloxi balance spring. Both releases are the product of some 25 years of development between both movement technologies to effectuate a common result: Preserve the accuracy and function of the movement against external forces such as magnetism.
The future of watchmaking for Rolex appears to be pointing in more than one direction. Perhaps it is hedging, or perhaps it believes strongly in both movements for which it holds patents. It could even be that Rolex is sticking with Parachrom because it views it as a point of distinction. No matter how you look at it – Chronergy escapement or not – all of the models in Rolex’s arsenal are accurate to the same seconds-per-day standard and are amagnetic without the need of an inner shield. If nothing else, it will be interesting to see what Rolex does with these two technologies going forward, but for now, the scales appear to be in balance.