For roughly two centuries, watchmakers have treated the balance wheel as sacred ground, the one place inside a mechanical movement where decoration was not allowed to go. It’s the component that, together with the hairspring, actually regulates a watch’s rate, and its mass and poise are calibrated to tolerances too fine for a single stone to disturb. Jacob & Co.’s new Brilliant Flying Tourbillon Baguette Pastel Arlequino breaks that rule outright, setting the balance wheel itself with 54 brilliant-cut diamonds, and, more unusually, getting away with it.
It isn’t the first time anyone has tried. Swiss and French watchmakers experimented with diamond-set balance wheels back in the 1820s and 30s, but those watches ran on cylinder escapements loose enough that a few minutes of daily drift barely registered, so the extra weight of a stone cost nothing anyone noticed. As chronometric standards tightened over the following century, the practice quietly died out, and gem-setters redirected their attention to bridges, rotors and cases instead, anywhere that wouldn’t touch the watch’s actual timekeeping. Jacob & Co. is reviving a technique modern watchmaking effectively abandoned, and doing it under standards the original watchmakers never had to meet.
The engineering payoff doubles as the visual one. The diamond-set balance wheel oscillates at 3Hz while the flying tourbillon beneath it completes a full rotation once a minute, two independent motions constantly shifting how light catches each stone, so the regulating organ reads less like a mechanism and more like a slow-moving halo. It’s a rare case of a technical solution and a decorative effect arriving from the same problem.
The rest of the watch commits to an unusual idea of its own. Rather than chase the saturated stones high jewelry usually prizes, deep sapphire blue, rich emerald, vivid ruby, the case, dial, crown and buckle are set with 366 sapphires chosen specifically for their pastel, imperfection-revealing softness. They’re arranged so neighboring stones clash rather than blend, green against blue, lavender against pink, unified only by a matched tonal lightness that keeps the deliberate discord from reading as chaos. Jacob & Co. calls the pattern Arlequino, after the harlequin of Italian commedia dell’arte, and the reference holds: nothing here is meant to melt into its neighbor.
Inside is the new caliber JCFA02, a self-winding flying tourbillon movement with a micro-rotor, a 72-hour power reserve, and 234 more diamonds set into the bridges visible through the caseback. The case itself, 42mm and just 11.61mm thick in 18K white gold, is smaller than past Brilliant Collection pieces without losing any of the family’s density of stonework. It arrives as a pièce unique, priced at USD 693,000.
