One of the advantages of mechanical wristwatches is that with a little tender loving care, they can run non-stop and consistently years and for much longer than what a battery powered wristwatch can run. Precision machined gears, pinions, and staffs contribute to a watch that runs as consistently as, well, a Swiss watch. Despite the engineering, mechanical watches have one Achilles heel and that is magnetism. Fortunately, Rolex addresses magnetism with Parachrom, a niobium, zirconium and oxygen ally that is 10 times less susceptible to shocks and unaffected by magnetic fields.
Magnetism is found all over the globe (just look at a compass) and is more prevalent in the industrial world. MRI machines, laptops, stereo speakers, cell phones all produce magnetic fields that can raise havoc with a mechanical wrist watches. All mechanical wristwatches utilize a hairspring in the balance wheel that if magnetized, the coils of the spring stick together rather than expanding and contracting normally. A magnetized hairspring will make the watch run exceedingly fast (eg. 15-30 minutes/hour) because a magnetized hairspring is effectively shorter thus making the balance wheel run faster. Most watchmakers have de-magnetizers to repair magnetized hairsprings. It is a simple fix, but it does require a trip to the watchmaker.
Time for some Metallurgy
Before Parachrom, Rolex utilized balance springs made from Invar, an anti-magnetic alloy that has high resilience, but it not totally anti-magnetic. Invar hairsprings are found in most mechanical watches and are typically made by Nivarox, a subsidiary of the Swatch Group. Nivarox came about in 1933 and is comprised of 45% cobalt, 20% nickel, 20% chromium, 5% iron and smaller percentages of titanium and beryllium.
After experimenting for several years, Rolex quietly introduced Parachrom in 2000 outfitting the newly designed Rolex Daytona. Rolex did not make a point of advertising its new hairspring other than including it in its all new in-house chronograph movement. Prior to 2000, Rolex modified chronograph movements from Zenith. Parachrom is made of entirely non-ferrous metals comprising of 85% niobium and 15% zirconium. Starting in 2005, Rolex covered the hairspring with a thin layer of blue oxide and officially rolled out the new hairspring as Parachrom Blu.
With five years of testing under its belt in the Rolex Daytona, the Parachrom Blu hairspring has been included in all the new Rolex updated designs, and was crucial in reintroducing Rolex’s late 1950’s era watch, the Milgauss in 2007. Other watch companies have looked to Silicium hairsprings for their anti-magnetic properties. Although Rolex was one of the early financial backers on Silicium development, Rolex choose to outfit its modern wristwatches with Parachrom Blu. Parachrom Blu is yet another development that separates Rolex from the rest of the field.