Who hasn’t pondered the age-old paradox: which came first, the chicken or the egg? There’s no definitive answer. Similarly, when discovering a new watch, revealing the behind-the-scenes development process raises a similar question: was the movement designed before the case? Or the other way around?
At Richard Mille, there’s nothing mysterious about it. The approach is consistent across every model. “From the very start of a project, every discipline is brought in,” explains Salvador Arbona, the brand’s Technical Director. “We engage in deep discussions with the teams to determine the direction to take. It’s not about making things complicated for the sake of it—everything must be coherent and show a certain restraint. We always aim to put the technical aspect at the forefront.”
In Full Transparency
This philosophy is brought vividly to life in the RM 75-01 Sapphire Flying Tourbillon. The timepiece combines Richard Mille’s uncompromising mechanical standards with the complete transparency of a case entirely machined from sapphire crystal. The technique isn’t just highlighted—it becomes a spectacle. The flying tourbillon moves within a crystalline structure that erases boundaries. Light passes freely through the case, spotlighting the finely finished components of the RM75-01 movement—such as the flying barrel, the centrally positioned minute wheel bridge, and, of course, the regulating organ.
Engineering the Transparent Case
The various parts that make up the brand’s iconic tonneau-shaped sapphire case are the result of a close partnership with Stettler AG. This Swiss company has mastered the Kyropoulos process—a variation of the Czochralski method, developed in the early 20th century by the Polish chemist of the same name. This technique involves growing a sapphire crystal from a small "seed" placed in contact with molten aluminum oxide, heated to between 2000 and 2050 °C. As it slowly solidifies around the seed, the crystal grows layer by layer, maintaining a perfectly uniform structure. The slow growth process, which can take several days or even weeks, produces high-quality optical-grade monocrystals weighing several kilos.
A Touch of Color
While the process of creating clear sapphire is now well-mastered, producing colored sapphire adds another level of complexity. Again, precision is critical. Adding pigments or metallic oxides to the base material must be done with extreme care to ensure even coloring, without compromising the crystal’s purity or durability.
In addition to its remarkable ability to diffuse light, sapphire is known for its exceptional hardness—second only to diamond—which makes it highly resistant to scratches and shocks. On the flip side, shaping it to the required dimensions demands extraordinary patience. Over 1,000 hours of work—350 of which are dedicated solely to polishing—are needed to create the curved, three-part case. The middle case, bezel, and caseback of the RM 75-01 come in subtle shades of pink or blue, depending on the version.
This is where haute horlogerie takes on a unique expression: transparency isn’t just an aesthetic choice, but the result of a technical tour de force. The union of sapphire crystal and a flying tourbillon gives rise to a standout piece that merges extreme mechanical sophistication with striking visual lightness. A paradox elsewhere, but a reality at Richard Mille.
