The unique case shape and digital time display of the 4N watch has been around for a few years now, and for 2015 it receives its most notable – and somewhat unexpected – update yet: the 4N Sapphire Planet wraps the original digital-mechanical movement in a sapphire crystal case.

“Sapphire.” Even the way it sounds is something special: it comes off as something expensive and refined, and it, in fact, is considered by many to be an essential component of a quality watch. Despite all that, sapphire crystal is a relatively common material in watchmaking, found even in couple-hundred dollar timepieces – and up, of course. It is used for the front and sometimes the back crystals for its remarkable scratch resistance and superior optical quality, when compared to mineral crystals or plastics. Sapphire crystal, however, does become a much more luxurious and genuinely exotic material when it is used not just for the front crystal, but also as the full case of a watch. The 4N Sapphire Planet offers not just that, but matches the sapphire case with an unusual digital-mechanical movement.

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We have written a number of times before about the 4N – for some cool hands-on images, video, and a detailed explanation visit our hands-on article of the 4N 4N-MVT01/D01 watch here – so today, we will only briefly cover its key features once again. The 4N watch was designed by a certain Francois Quentin who had worked with Hautlance and Louis Vuitton before setting off to come up with this very unique creation – a mechanical movement which indicates the time through a “digital” display.

What that actually means, is that the completely mechanical movement features a number of overlapping and rotating discs which make for a digital-like time display – something reminiscent of what you would find on much, much more usual items like, say, an alarm clock, microwave oven or your phone. It’s a deceptively simple concept, because to create the digital layout and jumping effect in a mechanical timepiece, a 514-component caliber had to be created. After a limited production run in white gold, rose gold and titanium, 4N will debut a 46mm wide, sapphire-cased version at BaselWorld 2015.


That comes as rather unexpected, as sapphire-cased watches have always been extremely rare. The reason for that is simple: sapphire is remarkably difficult to work with (massive understatement), because it is prone to cracking and must only be machined at a very, very slow pace. When it comes to complex shapes – which all cases suddenly become the moment you try and cut them from 1-3 blocks of sapphire crystal – creating the finished component can require days of work and if it cracks at the final stage, it must be thrown away.

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Every once in a while, someone does have a go at it – meaning, they find a specialist who can work with such tolerances. Notable examples from the past include the Richard Mille RM056, the MB&F HM2, and the Cecil Purnell Mirage. Cartier also had a go at creating a completely transparent case with the Cartier ID Two, although that actually was made from Ceramyst, a transparent ceramic – having used such a high-tech material instead of sapphire crystal goes to show just how difficult sapphire crystal is to work with. There may be a few others out there in existence, but these prove the point of just how few-and-far-between sapphire-cased watches are.

The 4N Sapphire Planet, while a fascinating and fitting entry to this closed circle of luxury timepieces, won’t add too much to it in terms of sheer volume as it is limited to just 3 pieces, with custom colors and markings; priced at €280,000 or around $310,000 USD each. We look forward to seeing the first finished piece in just a few weeks from now at BaselWorld 2015. 4nparis.com

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