Top-tier watchmaker Greubel Forsey debuted their original invention, the Double Tourbillion, inside a ceramic case for the first time ever today. Limited to 11 numbered pieces the Double Tourbillon 30° Technique Ceramic is presented in blue ceramic with sapphire crystal added to parts of the movement to let additional light in compared to previous versions.
What has remained the same is the Double Tourbillon 30° complication, which assures high accuracy. One cage rotates completely every four minutes while a smaller cage containing the balance wheel and spring, inclined at an angle of 30° relative to the larger cage, completes its revolution every 60 seconds. The combination of the 30° inclination with the different rotational speeds of the two tourbillons improves timekeeping by averaging out positional errors due to gravity.
The hand-wound 3Hz movement measures 38.40 mm x 12.15 mm, has 421 components, 120-hours power reserve, and 43 Olived-domed jewels in gold chatons. Driving the power reserve are four coaxial series-coupled fast-rotating barrels (1 turn in 3.2 hours), one of which is equipped with a slipping spring to avoid excess tension, with a 22k gold cover with nickel-palladium treatment and relief engraving. Many of the components are now sapphire, which lets more light in particularly enhancing the view of the double tourbillon at work. There are also traditional materials that remained from the previous movement iteration that include nickel silver, frosted with polished beveling and countersinks, straight-grained flanks, and nickel-palladium treatments.
Housing this movement is the new blue ceramic case which measures a not-insignificant 48.40 mm x 17.77 mm but is lighter than previous editions due to the ceramic material. The crown is also ceramic and is engraved with the GF logo. The caseback, bezel, and caseband are machined from a block of ceramic, polished and straight-grained, and hand-finished.
The Double Tourbillon 30° Technique Ceramic is water-resistant to 30 meters and comes on a rubber strap with a titanium buckle. Retail is $695,000.