RM 56-02 Sapphire Tourbillon (2014)
The third and most recent iteration in Richard Mille’s line of sapphire tourbillon timepieces is the RM 56-02 that features a case, centre bridges, tourbillon and barrel made entirely out of sapphire crystal, as well as a movement suspended from an elaborate cable and pulley system. The specially developed single suspension cable is braided to 0.35mm thick and manipulated via pulleys situated at the movement’s four corners and additional points along its periphery. A ratchet at nine o’clock regulates the tension of the cable, while an arrow-shaped indicator at 12 o’clock allows easy examination of the tightness of the cord. This movement construction was originally used on the RM27-01 Rafael Nadal watch with the sole purpose of withstanding shocks and hard hits. Manufacturing the curved three-part case was particularly difficult because sapphire crystal is an extremely hard and scratch-resistant material. Experts Stettler in Lyss, Switzerland milled and ground the case from blocks of sapphire crystal, which cracks easily. It takes 40 days of round-the-clock machining to produce one RM 56-02 case while the movement bridges require an additional 400 hours of machining and finishing. Only 10 pieces of the watch will be made.
The first watch made entirely in sapphire crystal Price: US$2.02 million