keep my inbox inspiring

Sign up to our monthly newsletter for exclusive news and trends

Follow us on all channels

Start following us for more content, inspiration, news, trends and more

© 2020 - Copyright Fondation de la Haute Horlogerie Tous droits réservés

The heir transparent

The heir transparent

Monday, 11 April 2016
Editor Image
Fabrice Eschmann
Freelance journalist

“Don't believe all the quotes you read online!”

“In life as in watchmaking, it takes many encounters to make a story.”

Read More

7 min read

Sapphire cases are becoming an increasingly common sight. Richard Mille, a trailblazer in 2012, has made sapphire-cased watches a speciality, with others following suit. A closer look at one of watchmaking’s newest phenomena.

A mere ten years ago, it was still mission impossible. Not a single supplier, not one specialist, in or outside Switzerland, had the necessary technology or competencies. Now it’s a question of who’s next. First Richard Mille, then H. Moser & Cie, Rebellion, Hublot, MB&F… the list is long of brands that are adding a sapphire case to their collections. The hardest mineral after diamond and notoriously difficult to machine, since 2012 this synthetic crystal has been the subject of considerable developments in watchmaking. Once limited to two dimensions, it can now be machined from a block on a five-axis CNC machine. This was all watchmakers needed to unleash their creativity and push the limits of possibility.

French chemist Auguste Victor Louis Verneuil was first to produce synthetic sapphire, in 1902. He gave his name to the flame fusion process whereby aluminium oxide powder is heated at over 2,000°C. The resulting carrot-shaped mass, known as a boule, is used to produce components for a variety of fields, such as optical, medical, aeronautics and microelectronics. The synthetic sapphire used in watchmaking, where demand is highest, is used to manufacture crystals. Its extreme hardness (9 out of 10 on the Mohs scale), excellent thermal stability and high transparency, due to its crystal structure, make it the ideal material with which to protect the dial, but also for casebacks that leave the movement visible.

Richard Mille was first to enter the fray, shaking up the 2012 Salon International de la Haute Horlogerie with the RM 56.
First off the blocks, Richard Mille

The problem with the Verneuil process is that the diameter of the boule rarely exceeds 45 mm. This, and sapphire’s brittleness, explains why for many years Swiss companies only worked with flat pieces. When orders started bypassing their books for overseas suppliers whose price/quality ratio was almost impossible to match, it was time for action, prompting a handful of Swiss firms to specialise. In doing so, they turned to another method for producing synthetic sapphire, the Kyropoulos technique, in which the aluminium oxide is melted in a crucible then slowly cooled into a block. This has the advantage of growing a larger crystal which has the almost perfect homogeneity of a boule: two characteristics that opened the floodgates for some extraordinary ideas.

Richard Mille RM 56-01 Tourbillon Saphir
Richard Mille RM 56-01 Tourbillon Sapphire

Richard Mille was first to enter the fray, shaking up the 2012 Salon International de la Haute Horlogerie with the RM 56. Limited to five pieces, this tourbillon split-seconds chronograph with power-reserve indicator, torque indicator and function selector had tongues wagging as much for its sapphire case as for its price: a cool CHF 1.9 million. This was a technology that didn’t come cheap. Four years of research and development preceded this three-dimensional exploit for which everything had to be reviewed and revised, from the diamond cutting tools on the CNC machine to the polishing process, an essential step to ensure the complete transparency of the finished piece. Made from three parts assembled by titanium screws, it takes over 1,000 hours to produce such a case, including 430 hours to pre-form the parts and 350 hours for polishing.

Richard Mille RM 56-02
Richard Mille RM 56-02

From that point on, there was to be no stopping Richard Mille. The RM 56-01 Tourbillon Sapphire, revealed in 2013, boasted not only a sapphire case but also a sapphire baseplate, centre bridge and third wheel. The following year, the RM 56-02 added a sapphire barrel bridge and tourbillon bridge to the mix, both redesigned for the occasion. It also adopted the cable-suspended movement developed for the RM 27-01 Rafael Nadal, lending new significance to the transparency of the case that reveals every detail of this fabulous mechanical architecture. Last year’s RM 56 Felipe Massa Sapphire borrowed the contours and the movement of the original RM 56, while introducing a new design for the dial and crown.

While not a year has gone by since 2012 without the launch of at least one sapphire-cased watch, 2016 is proving to be an exceptional vintage.
Sapphire's big year

Produced as limited editions of five or ten, and carrying price tags around the CHF 2 million mark, it wasn’t long before Richard Mille’s watches were giving other brands ideas. Beginning with H. Moser & Cie which came to the Basel watch fair in 2015 with the Venturer Tourbillon Dual Time Sapphire Skeleton. As well as its sapphire case, this one-off piece has the particularity that its rubber strap is made using a 3D printer. “I wanted to show that the classic register of H. Moser & Cie can be a particularly inspiring playground, although I must admit it proved more complicated to put into practice than I had anticipated!” observes Chief Executive Edouard Meylan. The price of exclusivity: CHF 1 million.

H. Moser & Cie Venturer Tourbillon Dual Time Sapphire Skeleton
H. Moser & Cie Venturer Tourbillon Dual Time Sapphire Skeleton

While not a year has gone by since 2012 without the launch of at least one sapphire-cased watch, 2016 is proving to be an exceptional vintage. Recent weeks have seen new and sometimes multiple offerings from the likes of MB&F, Rebellion, Hublot and of course Richard Mille. A limited edition of ten in red gold and ten in platinum, the HM6 SV by MB&F is without doubt the most complex in terms of case construction. It is assembled from 11 parts, including hollow half spheres, which are vacuum-sealed at high temperature. “The idea of a transparent case has been at the back of our minds ever since MB&F began,” comments head of communications Charris Yadigaroglou. “The movement of the HM6 is just so wild, with its 500 parts, that we couldn’t imagine not showing it off.” Wild it may be; at CHF 350,000 and CHF 380,000 respectively, it isn’t the most expensive.


Rebellion, a small, independent brand with its own racing team, Rebellion Racing, has its way of thinking. “Given that a diamond tool lasts between 20 and 30 minutes, and knowing that it took 47,600 minutes to machine this case, the extent of the challenge becomes clear,” says Chief Executive Philippe Dubois. “The Magnum 540 Tourbillon Sapphire is a one-off piece by watchmaker David Candaux that is worth CHF 1.8 million. Probably we’ll combine it with one of our cars, a winner at the 24 Hours of Le Mans, that is equally unique!” Yours for CHF 4 million.

Colour is the latest trend in sapphire cases.
Think pink

This year also marks a turning point in terms of production. Until now, sapphire watches were proposed as one-off pieces or at most in very limited editions. Suddenly, we’re seeing series of 500 pieces at a time. Or so it is with Hublot’s Big Bang Unico Sapphire. A project whose “large scale” translates into a reduced price of CHF 55,000. A figure in sharp contrast with the CHF 500,000 which the highly conceptual MP-05 “LaFerrari” Sapphire will set you back. Limited to 20 pieces, it delivers a 50-day power reserve thanks to the 11 barrels stacked vertically along its centre.

Richard Mille RM07-02
Richard Mille RM07-02

After increased production leading to lower prices, another trend is beginning to emerge in sapphire watches, and that is colour. Richard Mille’s RM 07-02 Pink Lady Sapphire Automatic is machined from sapphire that has been coloured in the mass. Hublot, meanwhile, pulled a Big Bang Unico Sapphire All Black, priced CHF 60,000, out of the bag at Baselworld 2016. In this instance, the sapphire is coated with metal. Sapphire clearly hasn’t said its last word…

Back to Top