First things first, what is sapphire crystal? Essentially, it’s the same stuff used to make a watch ‘glass’ and display casebacks, formed by crystallising aluminium oxide at very high temperatures to create an extremely hard material. Roughly speaking, it mimics what Earth has taken 400 million or so years to do, to form natural sapphire gemstones. For sapphire-cased watches, the middle, bezel and back are milled from solid blocks of the material. Because it’s almost as hard and scratch-resistant as diamond (9 on the Mohs scale, as opposed to 10 for diamond), the task of milling it into the complex shapes required is much more easily said than done. Indeed, sapphire crystal can be cut only by diamond.
Harnessing the knowledge it gained from developing a milling technique for Magic Gold (another hugely challenging material), Hublot works with a Swiss specialist as part of an exclusive partnership to develop the sapphire material.
Speaking at Baselworld 2016, Ricardo Guadalupe, Hublot’s CEO, said that the rationale for using the material was to show off its in-house calibres – and that would also determine the choice of models that would be given sapphire cases.
2016 MP-05 LaFerrari
After 18 months of development work, Hublot revealed its first foray into sapphire case-making – on a watch with by far the most complex case shape in their range. It’s as if they had decided, “If we can make this one, we can make anything.”
The cobra’s head shape of the replica limited MP-05 case had been designed to show off the movement, with its suspended vertical tourbillon and series-coupled time-display rolls and vertical tourbillon. In the sapphire version, the movement seems to be suspended inside its transparent cocoon, with no visible means of support. The case middle is composed of seven components carved from seven blocks of sapphire using 3D machining. Requiring more than 600 hours of machining, polishing and assembly work, the LaFerrari case weighs a mere 53.5 grams. For good measure, Hublot used transparent materials for most of the display cylinders and added a semi-transparent silicone strap with some clasp components also milled from sapphire crystal.
2016 Big Bang Unico Sapphire
Did Hublot think it hadn’t made things clear enough with the MP-05? Turning to more conventional shapes, they milled Hublot fake 500-piece limited edition Big Bang (the largest production run of a sapphire case), with the case middle, bezel and back made from three blocks of sapphire, calling on the expertise of a Swiss specialist as part of an exclusive partnership to develop the material. Combining the colourless sapphire case with a transparent resin dial and skeleton work it made the movement (the in-house automatic flyback chronograph movement, cal. HUB1242) almost entirely visible. Or should we be saying invisible? Enhancing the effect, the strap is made from almost-transparent silicone. This combination of elements set the parameters for all of the Unico Sapphire models that have followed.