Transparency has become a hot topic in the luxury watch world, especially when it comes to using transparent materials for watchcases. Now, Greubel Forsey— a brand known for its incredible three-dimensional super-complicated watches—unveils its famed Double Tourbillon 30° Technique in an all-sapphire case. The result is an unobstructed observation of each separate element of the carefully engineered and assembled movement, and a look at their incredible interactions.
The Sapphire watch—created in a very limited edition of just eight pieces—is a US exclusive. What makes the timepiece even more intriguing is that Greubel Forsey, unlike others who turn to sapphire for cases, did not use multiple pieces of crystal for the case and sides. Instead, the brand has machined the entire 38.4mm case from a single sapphire crystal—this includes the case, sides, and horns.
While the 396-part movement inside this new Sapphire version is not new, its architecture is now unobstructed by a metal case. In fact, the complicated, patented tourbillon movement was first developed and unveiled to the world in a platinum case—but that case defied the true raison d’etre of the watch—showing off the movement.
The hand-wound caliber is an incredible feat of technical prowess, in that it houses two tourbillon escapements (a device that compensates for errors in timekeeping due the effects of gravity when the watch is in certain positions)—one inside the other. By utilizing double tourbillons—each rotating at different speeds (the outer one rotates once every four minutes while the inner one rotates every 60 seconds)—Greubel Forsey was able to achieve an unheard-of score of 915 out of 1,000 points at the International Chronometry Competition five years ago.
The Double Tourbillon 30° Technique Sapphire offers 120 hours of power reserve thanks to its four co-axial series-coupled, fast-rotating barrels. You can read a lot more about the technical aspects of this watch here. As previously stated, this purely transparent version is a US exclusive and each of the eight pieces are expected to sell for about $1.1 million.