The fantastic qualities of sapphire have been used to enrich high-end watches for many years. Sapphire crystal, whether natural or synthetic, is one of the hardest substances on earth, almost as hard as diamonds. Synthetic sapphire is formed by crystallising pure aluminium oxide at exceedingly high temperatures to form a single crystal structure that is transparent, virtually scratch-proof, and so hard that expensive tools are required to cut and polish it.

Nevertheless, major names in watchmaking are harnessing sapphire’s desirable qualities to produce innovative timekeeping instruments that push boundaries. Ultimately, sapphire crystal is favoured because of its clarity, durability and longevity, scratch-resistance, anti-reflective properties and high-temperature tolerance. Most often it appears as a protective crystal dome over the watch face and a transparent caseback to showcase the movement, but it can also be utilised for the entire watch case, the bezel, and on the hands to protect against shock.

Hublot has used all the fine qualities of sapphire to create the Spirit of Big Bang Sang Bleu watch. In this visually stunning creation, celebrity Swiss tattoo artist Maxime Plescia-Buchi of Sang Bleu studio has transposed his three-dimensional geometric craftsmanship onto a new iteration of the famous watch, imparting depth, transparency and aesthetic distinctiveness. The complexities of the polygonal tattooing necessitated machining sapphire that stretched the technology to its limits. Despite this, the Big Bang spirit remains intact, including its 42mm diameter and barrel shape. Sapphire features prominently, from the dial, with the HUB4700 self-winding skeleton chronograph clearly visible, to its case and bezel.

It takes more than 100 hours of work for the incised, chiselled, angled and faceted features of this watch to be machined into the hardness of the demanding sapphire material. Amazingly, the only non-transparent elements of the timepiece are the crown, the push buttons, the screws on the case, the 6 H-shaped screws on the bezel, and the folding clasp.

Hublot has also released a Big Bang MP-11 Water Blue Sapphire watch, with its seven-barrel, 14-day power reserve movement, in an alluring “glacier blue” shade. The novelty is based on a new chemical formula that retains the brilliant, luminous, transparent and resistant qualities of sapphire while also acting as a magnifier for the emblematic barrel of the timepiece.

Limited to 25 pieces a year, Armin Strom’s Gravity Equal Force Ultimate Sapphire Purple watch has a grey-toned off-centre dial utilising transparent sapphire crystal. Only seen in the Ultimate Sapphire editions, this material brings out the elegance of the purple main plate handcrafted in the atelier of Finnish watchmaker Kari Voutilainen with a guilloché-engraved barley-grain motif. This vibrant hue adds additional panache to a range noted not only for its transparency but also for being the first automatic watch endowed with an equal-force transmission integrated into the mainspring barrel, providing consistent power transmission and ensuring constant precision.

Just unveiled at Geneva Watch Days, the Flying Tourbillon Grande Date B1.618 Sapphire White from Swiss tourbillon watchmaker Bianchet is noted for being the first sapphire crystal case to integrate rubber seams into its construction. This remarkable fusion of materials and technology specifically made for this watch affords an unerringly clear perspective of the intricate movement housed within the softly curved tonneau case. In a timepiece limited to 21 pieces, the titanium-made components of the flying tourbillon appear to float – a trick of the ball-bearing mechanism – and are arranged under the principles of the Fibonacci spiral.

Harry Winston’s Ocean Biretrograde Diamond Waves Automatic 36mm model also utilises an open, transparent caseback made of sapphire crystal to reveal the intricacies of its HW3302 movement. This addition to the Ocean Collection has a white beaded mother-of-pearl dial set with streams of baguette-cut diamonds (51 in total) and baguette-cut blue sapphires (33). These precious embellishments to the watch face allude to the aquatic spirit of the collection and the movement of waves.

Limited to just eight models, HYT’s Conical Tourbillon Infinity Sapphires timepiece fuses innovative tourbillon design utilising a spiral balance inclined at 30 degrees with the aesthetic allure of sapphire gemstones in its construction. Three strikingly coloured and rotating sapphire gemstones – in fuchsia, blue-grey and yellow – guard the periphery of the conical tourbillon while also serving to magnify the watch’s breathtaking heartbeat. Six slightly smaller sapphires rest within the tourbillon’s brackets, further elevating the attraction of the animated display, which is boldly encased in rose gold and black titanium and protected by a sapphire crystal dome.

Dressed with anti-reflective coating, the tough, translucent and scratch-resistant sapphire that forms the 45mm case and caseback of the BR 01 Cyber Skull Sapphire Ice Blue watch by Bell & Ross is derived by melting alumina powder to temperatures exceeding 2,000°C. With aesthetics influenced by aeronautics, a dial composed of skeletonised faceted sapphire contrasts with the boldness of a blue anodised steel skull that sports a mocking smile. The mechanical BR-CAL.209 movement boasts a 48-hour power reserve and animates the skull and jaw of this remarkable 25-piece edition.

Utilising a case cut from a block of a standout material called NanoSaphir, the Tiny Purity Tourbillon NanoSaphir Chameleon watch by ArtyA exhibits a stunning light show on the wrist. While all the time maintaining clarity, its colour shifts in response to changes in ambient light. Treatments designed to alter the material’s optical properties mean that this high-tech, tinted synthetic sapphire will change from amber-orange to bright green depending on whether it is exposed to natural or artificial light.

Sapphire blue CVD coating distinguishes the striking dial of the Chronoswiss Delphis Sapphire watch, which also catches the eye with its three-dimensional construction and hand guilloché. Limited to just 50 pieces, it features the signature elements of the range – jumping hours, retrograde minutes, and oversized onion crown – in a case protected by double anti-reflective sapphire crystal. The transparent crystal extends to the satin-finished screwed-down caseback, further enhancing its durability and water-resistance qualities.

Multi-coloured precious sapphires embellish an exquisite iteration of Damiani’s Margherita Watch. This line of secret watches dazzles with a design derived from the shape of daisies.