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<< Back to Robb Report, 2014 Watch Collector

Taking a seat at the bench in the workshop of Bunter SA, one of the watch industry’s most renowned gem-setting specialists, it is easy to understand how in Switzerland, the setting of diamonds is as technical and precise an art as the crafting of the watches themselves. While some stones are set with hand tools as they have always been, Bunter’s most challenging and celebrated practice, the invisible setting of diamonds, bears a resemblance to modern microsurgery. The work is planned with three-dimensional CAD programs and executed on special machines under the guidance of microcameras.

Invisibly set diamonds appear to be floating side by side without any apparent support, and each stone must rise above the surface to exactly the same height as every other diamond in the watch. To achieve this, the gems are grooved along the pavilion (the lower portion of the stone), allowing it to be snapped onto a metal grid just below the surface. The grooves are measured and cut to within tolerances of one-hundredth of a millimeter—“this is less than one-tenth the thickness of a human hair,” says Bunter owner Claude Sanz. Using proprietary technology, Bunter has the ability to groove diamonds as small as 1.5 mm in circumference, an important distinction since many of the stones, such as a tiny stone set into the side of a crown, are miniscule.

Invisible setting has been used in jewelry for more than a century. In watches, where the stones have to convey the precise lines of a case, the standards for setting are all the more exacting. Creating a perfect surface that reflects light uniformly—a skill in which Bunter excels—means the grooves on the pavilions, as well as Sanz’s techniques for precisely cutting them, are crucial. It can take up to 30 minutes to cut one diamond in a watch that might contain over 1,000 gems.

Mistakes can also be costly. The convention in gem setting for watches is to use the highest quality diamonds—defined by the old-world term “Top Wesselton,” meaning a clarity and color grade among the top 1 percent mined in the world. Just shaving the pavilion off a Top Wesselton to keep it out of the way of a winding stem or a gasket can add considerable wastage cost to the endeavor. At Graff, the British diamond company that began producing a line of diamond-set watches in 2009, special cuts are a normal part of production. Many of its most exclusive models, like its MasterGraff Skeleton and Tourbillons, are designed not only with specially tapered baguettes, but with fancy-cut diamonds that must be adjusted and interlocked to form the bezels and other surfaces of these timepieces. The sheer scale of Graff’s diamond business makes this level of specialized cutting a practical endeavor.

Having a high degree of expertise may be the next best thing for Franck Muller. Vartan Sirmakes, CEO of the Franck Muller Group, owned a case maker specializing in diamond-set watches before he co-founded Franck Muller in 1991. Today, at least half of the company’s production is comprised of gem-set pieces, with all of the setting done in-house. The company’s access to diamonds in white and fancy colors has clearly sparked creativity in the company’s design department, which has extended the reach of the company’s setters to the movement itself. A recent feat involved setting diamonds on the bridges and the plate of the Giga Tourbillon.

Even for companies without directly sourced stones, the skill involved in gem setting bestows value to a watch second only to high complication, and conveys corresponding prestige. The latest in Chopard’s ­statement-piece jewelry watches is the new Happy Sport Diamantissimo, set with 958 baguette-cut diamonds and 1,978 brilliant-cut diamonds. Chopard’s roots as a jewelry maker is an overt message carried by the full range of techniques used in each of these timepieces.

Although Corum leans toward suave design rather than jewelry, its new Admiral’s Cup Legend 38 Haute Joaillerie, set with 1,444 diamonds and pink sapphires, carries a message as well. “We decided to bring forward our creativity specifically through a unique and, until now, never-presented technique at a high level of complication,” explains Corum CEO Antonio Calce, who says it took 1,300 hours to produce the dial alone. The dial, like that of the Chopard Happy Sport Diamantissimo, is set mosaic-style, an adaptation of the invisible setting that aims for a pattern on the dial. What these two watches also add to the mix is that they contain top-notch mechanical calibers, rather than the quartz movements that traditionally drive jewelry watches. Corum has also utilized the winding rotor as a setting for diamonds and pink and purple sapphires.

Setting the rotor is in fact emerging as one of the most creative innovations in watchmaking, and it is likely to remain a classic canvas for the decoration of women’s timepieces in the future. Dior, Harry Winston, Cartier, and De Grisogono have all introduced watches recently with “inverse” movements, in which the rotor is located on the dial side of the watch, rather than the back, and is often set with diamonds. Several brands have explored setting gems on other components of the movement, including Chanel, with a diamond-set cage on its Camélia Flying Tourbillon, and Hublot, with jewels on the bridges of the skeletonized Classic Fusion Haute Joaillerie One ­Million—which is set with a total of 1,185 baguette diamonds.

Snow setting is another technique that setters are now employing to freshen up traditional pavé. An adaptation of conventional claw setting, snow setting involves placing diamonds of varying sizes in a random, freeform pattern over the metal surface. The varying gem sizes and slight differences in setting angles produce a sparkling effect, like snow. Sanz proclaims snow setting has “a sweet name, but it’s the easiest thing in the world. You drill a hole, you set a stone, you drill another hole, and set the next one as closely as possible.” It may not be high-tech, but it does take an experienced hand and no small degree of artistry.

While the technical demands of gem setting remain among the least recognized arts in watchmaking, the variety of techniques now employed in many of the top pieces show that jeweling, like complications, is becoming a competitive area for watchmakers. Watch collectors will recognize the mix of technology and time-honored techniques now in play. Those who covet high-level jewelry watches can look forward to a similar level of creative activity in years to come. 

Chanel, 800.550.0005,; Chopard, 800.246.7273,; Corum, 954.279.1220,; Dior, 212.931.2950,; Franck Muller, 212.463.8898,; Graff, 212.355.9292,; Hublot, 800.536.0636,