Traditionally, glasses and watch backs are made of this material: sapphire crystal, in comparison with ordinary mineral glass, is much stronger (9 units on the Mohs scale), and besides, it is not covered with scratches, does not fade or cloud over time. Despite the fact that the high strength of sapphire glass makes it difficult to process it, modern technologies allow you to create almost anything from it.
Double Tourbillon 30 ° Technique, Greubel Forsey
The sophisticated tourbillon caliber is housed in a completely transparent case, as if in an aquarium: almost all 396 movement parts can be seen not only from the front, but also from the back and from the side. The entire case, including the lugs for attaching the strap, is made of a single sapphire crystal. There are only eight such watches produced, each worth $ 1.28 million.
BR X1 Tourbillon Chronograph Sapphire, Bell & Ross
Bell & Ross's recognizable 45mm square case has become completely transparent. It contains the hand-wound caliber R-CAL.285: it operates a flying tourbillon and a one-button chronograph.
Bugatti Supersport Sapphire, Parmigiani Fleurier
The skeleton of a rose gold case with five transparent sapphire crystal inserts underlines the noble volume of the Super Sport collection. All red gold bridges and platinum are perfectly polished, some details are covered with a decorative pattern "Côtes de Genève" - so the entire caliber appears before your eyes in its impeccable beauty.
MP-05 "La Ferrari", Hublot
The sophisticated "engine" of the MP-05 LaFerrari - Sapphire 637 - can be seen in detail through the sapphire crystal of the case. The fully transparent outer shell, reminiscent of the Ferrari bonnet, is composed of seven pieces, each artfully carved from a separate block of sapphire crystal. The watch "supercar" with a tourbillon is limited to 20 pieces.
Astronomia Sky, Jacob & Co.
This astronomical clock, under a sapphire dome of the case, is a planetary model of the rotation of the Earth and its satellite against a shimmering aventurine background. At the ends of the rotating "carousel" there is a flying tourbillon, a ball of the Earth made of gold and blue enamel, and the Moon - made of a briolette-cut diamond weighing one carat.
RM 07-02 Pink Lady Sapphire, Richard Mille
Avant-garde artist Richard Mill was one of the first to address the topic of movement transparency: his first watch in a sapphire crystal case RM 056 appeared in 2012. The novelty in a pink sapphire glass case (it takes 40 days to make) is addressed to the female audience of the brand. Mechanism details are made of rose gold, bridges and rotor are decorated with diamonds.
Big Bang Unico Sapphire, Hublot
The entire architecture of the HUB 1242 UNICO caliber is clearly visible through the transparent polished sapphire case. Only six branded screws, the crown and the buckle of the translucent strap are made of titanium. The watch is released in a series of 500 pieces.
Flying Tourbillon Ottantasei Pininfarina, Bovet
This complex masterpiece is a joint brainchild of the Dimier 1738 watch manufacture and the designers of Pininfarina. The transparent case is composed of four pieces of sapphire crystal combined with titanium and gold. Through it you can see the hand-wound caliber and the flying tourbillon providing a 10-day power reserve. Despite its impressive dimensions - 44 mm in diameter and 12 mm thick - the watch weighs only 51.66 g.
Vortex 02, Hautlence
The case of the avant-garde Hautlence watch is made up of six three-dimensional fragments of sapphire crystal, through which one can see the bridges of the movement and the two-level structure of the time indication, including the watch pointer in the form of a moving chain.
Horological Machine No6 SV, MB&F
The streamlined "space" case made of sapphire glass reveals the amazing mechanics of the "watch machine" invented by Maximilian Busser (the letters SV in its name mean "Sapphire Vision"). The wide metal ring of the platinum or rose gold case features horizontal stripes reminiscent of mid-20th century American buses. The watch is released in a limited edition of 20 pieces.>