Rolex’s Parachrom Bleu Hairspring is an in-house hairspring comprised of a paramagnetic alloy. The technology behind this hairspring was first introduced by Rolex in 2000.
Some of the topics covered in this caliber listing:
What was the first Rolex watch with the Parachrom Bleu Hairspring?
Many sites incorrectly state that the 116520 Daytona caliber 4130 was the first movement to feature the Parachom Bleu Hairspring. Technically a “Parachom” hairspring was indeed first used in Daytona watches starting in 2000, but it wasn’t blued. Improvements and the blue color were came in 2005.
“Bleu” is not a typo, it’s French for the word blue. For years, Rolex referred to this hairspring as being Parachrom Bleu, but as of this post they write it as Blue Parachrom. Some folks even write it as Blu.
Rolex loves to make up and use fancy verbiage for their products, and the story is no different in this case. Parachrom is said to be a combination of the words: paramagnetic and chrom.
When something is paramagnetic, it does not retain magnetism and is weakly affected by magnetic fields. “Chrom” comes from the Greek word for color which is chrôma. Bleu, as noted is French for blue.
In Rolex’s Own Words:
“After five years of research, Rolex created the blue Parachrom hairspring. Crafted from a paramagnetic alloy, it is unaffected by magnetic fields and up to 10 times more resistant to shocks. Historically, the unique blue colour of the hairspring has been a sign of prestige reserved for only the most accurate timepieces.”
Until the introduction of this hairspring, Rolex was using Nivarox (short for Non-Variable-Non-Oxidizing) hairsprings. Nivarox is owned by the Swatch Group, Rolex’s most fierce competitor.