Sapphire, from the Greek sàppheiros, “blue”, or from the Hebrew “sappir” or “the most beautiful thing”, identifies the blue-blue variety of corundum, which is chemically aluminum oxide and has a hardness equal to 9 on the scale by Mohs.
Sapphires can have the most diverse colors, from pink to orange, purple, green, yellow to colorless white; these variants are identified with the name of other stones, followed by the suffix “oriental”, for example the terms oriental amethyst and oriental emerald are today identified with the names of violet sapphire and green sapphire.
In 1902, French chemist Auguste Verneuil developed a process to manufacture synthetic sapphire crystals, which immediately found application in the field of watchmaking.
Indeed, sapphire crystal is made up of synthetic sapphire, usually used to make the protective screen of watch dials, thanks to its hardness it can only be scratched by boron nitride or diamond.
The idea that revolutionized modern watchmaking
Before the advent of sapphire glass, even large companies offered their customers dials enclosed in a plastic glass made of plexiglass preferred for its resistance, ease of molding and usability.
Unfortunately, however, while returning a very warm feeling much sought after by vintage lovers, this material also carries some potential issues, and did not always allow a clean and clear view of the dial.
According to history, sapphire crystal was firstly used by Jaeger LeCoultre in the early ’30s and subsequently by Omega in the ’50s
However, due to its high processing costs was never used systematically until the ’70s and ’80s when Rolex started using it on all its main models.
Tuttavia, a causa della difficoltà e dei costi di lavorazione non fu ma un utilizzo sistematico fino agli anni ’70 e ’80 quando Rolex iniziò ad utilizzare questo materiale su tutti i suoi modelli.
But why the choice of sapphire crystal? To find out, let’s walk the path of the evolution of Rolex together.
At the beginning of 1970, the Genevan house put on sale several models still made with the classic plexiglass, with the only element of discontinuity, already present on Rolex models since 1954, namely the Cyclops lens which was not in plexiglass but made from a lens magnifier for watches.
The choice of sapphire crystal will come more than fifteen years after the creation of the Cyclops lens making its debut on a very particular Rolex model, we are talking about one of the first quartz references of the company, the Quartz ref. 5100.
Undermined by the Japanese market and its new quartz models, Rolex also opts for a watch with this type of movement;
In addition to surprising its customers of the time with a non-automatic watch, the 5100 also stands out for its unprecedented stylistic choices, it is precisely with this watch, which stands out as different and innovative, that for the first time a prioritary carrure closure is manufactured to host the new synthetic sapphire dial which is more resistant to shocks and is also less prone to scratches.
The Rolex Quartz, however, was not as successful as expected, as only after two years of production this model was discontinued; despite this fact, we should credit the engineers who worked on the 5100 for the technological advancements that brought the sapphire crystal to where it is today.
Even though the model was not successful, the maison starts to use sapphire crystal in other models too.
The references that have the privilege of seeing this sapphire glass mounted, even if still inserted in the experimental phase, are 1630 and 1530. Precisely to check the performance of the sapphire and keep it firmer at the case, these watches present for the first time the Shaped case with an integrated bracelet inside, a technical solution used by many fashion houses, making their debut in the use of this innovative and performing crystal.
Nine years after Omega brought the Speedmaster into space, with its iconic hesalite crystal, Rolex creates the new Rolex Saphir 25-285 crystal for one of its most resistant and technical watches: the Sea-Dweller ref. 16660.
The Sapphire 25-285 made for the Sea Dweller is flat but at the same time more resistant, thanks to a thickness of about 3 mm, a feature that allows you to keep the glass in excellent condition even if subjected to strong pressure.
The implementation of sapphire glass for all models of the Rolex collections arrives during the ’90s.
Today the sapphire crystal has undergone several changes, as well as being more resistant, it is treated for all Rolex watches, with anti-scratch and anti-reflection to provide an always perfect view of the dial and its details.
From glass to cases, precious transparencies for fine mechanics…
The evolution in the use of sapphire in watchmaking has never stopped since it began in the ’70s, today we can admire unimaginable different ways and forms for the application of this material.
This success is partly owed to the work of one of the most influential italian watchmakers: Vincent Calabrese. In 1980 he created for Corum the first Golden Bridge with a full sapphire crystal case.
Nowadays, many manufacturers are trying their hand at the production of sapphire crystal cases, not only transparent, but also in different colors: from the most sober in smoky gray, to the most lively, as in the case of the case of the Spirit of Big Bang Yellow Sapphire. by Hublot.
The beginning of this new era was partly established by Richard Mille, when in 2012 presented the RM 056. However, let’s not forget the Hublot’s relevant role, who in 2016, when the brand led by Ricardo Guadalupe presented two series of watches with a sapphire crystal case: 20 units of the MP5 La Ferrari Sapphire in Geneva, and 500 pieces of Big Bang Unico Sapphire in Basel.
In the meantime the sapphire crystal case has become a widespread trend; several haute horlogerie houses have let themselves be tempted by the “transparent style”, creating models that have not always remained in the catalog.
The models launched in recent years are in fact very numerous, even if ephemeral, because generally they are limited series, if not very limited, destined to run out in a short time, especially if the maison that launches them has a certain “power of attraction” , making them go immediately sold out in spite of the price.
To better understand the complexity of processing a crystal sapphire case we avoid going into the details of the so-called “flame fusion”. For now suffice it to say that, through high pressure and very high temperature treatments, it is possible to create cylindrical blocks of sapphire glass, with dimensions consistent with the needs of watchmaking.
These cylinders then undergo long milling and turning processes, with grinding wheels and other diamond-tipped tools, the only ones capable of cutting, shaping and engraving them.
This would lead us to think that sapphire is a practically unbreakable, if not indestructible material, and in fact it is true that breaking it is extremely difficult, however it is not impossible, even sapphire crystal has a weak point: it can chip, fracture and even literally fall apart, which is not often the case, thankfully.
It goes without saying that we are talking about high production and finishing costs. The technology to produce a case in sapphire crystal has costs directly proportional to the size and thickness of the glass itself, as well as to the number of operations necessary to obtain the desired shape.
Of course it is never a trivial matter, even a simple round case with integrated lugs is not easy to make, let alone when the shape is more complex, perhaps with bevels, recesses, engravings, or holes for the buttons All steps that require time, right tools and competence, which obviously affect the costs of the final product.
This is the reason why the sapphire crystal case is used by the fashion houses in exceptional cases, with an eye to production costs, so that they do not excessively affect the final price.
So is it the future or just a trend?
The time has come to answer the question from which we started: is the use of Sapphire in watchmaking a passing trend or the future?
Certainly it was part of the evolution of watchmaking and a very important and functional innovation, just think of the use in diver watches, which allowed to increase the resistance to high pressures exponentially, in combination with increasingly advanced cases.
Undoubtedly, however, the use of sapphire in the creation of cases is showing an increase, as we have seen, there are many fashion houses that use them in more or less large limited editions, which immediately find the public’s approval.
In conclusion, thanks to its qualities sapphire is a very interesting resource for watchmaking. Moreover, the advancement in technology will make its processing easier so its implementation more common.
This therefore suggests that it is not a fashion of the moment, but a growing trend that will lay the foundations for the future of watchmaking, where fans are growing and movements are increasingly complex, worked and refined, not there is a better showcase to put them on display, if not a magnificent sapphire case, with its precious transparencies.
