Arnold & Son
Ultrathin Tourbillon Red Gold Onyx

Ultrathin Tourbillon Red Gold or Platinum, Onyx Edition

When darkest black becomes colour

One of the slimmest flying tourbillon watches on the market, the Ultrathin Tourbillon is available in 5N red gold or platinum, each in a limited edition of eight pieces. Its broad dial fully exploits the deep black of the onyx, enhancing the sweep of the regulating organ at 6 o’clock.

When John Arnold began his career in London in 1762, only a handful of leading watchmakers – including George Graham, Thomas Mudge and John Harrison – used pierced rubies to reduce friction at the pivots of the final wheels of the gear train and the balance. Long a closely guarded secret among English master watchmakers, John Arnold also employed this savoir-faire in jewels in the escapements of his marine chronometers and deck watches.

Commemorating expertise

Invested in the working of ornamental stones since its founding, Arnold & Son continues this tradition today by adorning select creations with fine and precious stones. For this edition of the Ultrathin Tourbillon Onyx, the Maison has chosen a 41.5 mm case with softly rounded contours, available in 18-carat 5N red gold or 950 platinum. It is framed by a slim bezel and fitted with a sapphire crystal, revealing a generously proportioned main dial.

Shades of black

The main part of the dial is fashioned from a finely polished disc of genuine onyx. A variety of agate from the large chalcedony family, this stone is defined by its dark, intense and enigmatic hue. It was selected for its aura of mysterious elegance, which emphasises the refined character of the Ultrathin Tourbillon. The concave hours-and-minutes sub-dial is also crafted from black onyx. True to its reputation for inventive use of fine stones, Arnold & Son breaks new ground here, exploring previously uncharted territory: for the first time in watchmaking, onyx is given a matt satin finish. Bold and complex in its execution, this treatment reveals a subtle interplay of materials and reaffirms the Maison’s expertise in the art of working with stone, pushing the boundaries of traditional mineral dial design.

The magic of contrast

Onyx has been associated with inner strength, courage and self-mastery since antiquity. Greek and Roman civilisations considered it a talisman, believing in its protective powers. Valued over the centuries, onyx has been widely used in jewellery, seals and ceremonial objects, where it has long symbolised power, authority and discernment. Rich in symbolism, it reveals its full magic here, showcasing the hand-bevelled cage of the flying tourbillon through a wide circular aperture at 6 o’clock in the thin stone disc.

A heart of gold

A truly refined movement was required to bring the Ultrathin Tourbillon Onyx – presented in 18-carat 5N red gold or 950 platinum – to life. At just 2.97 mm thick, the in-house A&S8300 manual-winding calibre is among the thinnest available today and fully meets the demands of this haute horlogerie timepiece. Visible through the sapphire crystal case back, the movement reveals its full sophistication. Its 32 mm diameter showcases exemplary finishing: radiating Côtes de Genève, chamfering, snailing on the two-barrel ratchet wheels, and polished, blued and chamfered screws. The flying tourbillon bridge is crafted in 3N yellow gold and hand-engraved with plant motifs inspired by those that adorned the balance cocks of John Arnold’s pocket watches.

A tale worth spinning

The large, delicate and elegant cage of the flying tourbillon tells a story through symbols. The stylised sextant evokes John Arnold’s pivotal role in advancing the calculation of longitude with his marine chronometers. And the anchor-shaped counterweight – whose central tip serves as a reference for reading the seconds as the cage completes its one-minute rotation – recalls the iconic designs of the renowned English watchmaker.

Always moving forward

To ensure optimal performance for the Ultrathin Tourbillon Onyx, Arnold & Son has reworked several components of the A&S8300 calibre. Among the key developments are the integration of a variable-inertia balance, refinements to the regulating organ, and modifications to the tourbillon cage. These changes significantly increase the power reserve, now extended to 100 hours when the watch, water-resistant to 30 metres, is fully wound. This enhancement further reinforces the exceptional character of the ultra-thin tourbillon timepiece.

A celebration of contrasts

Presented on an alligator leather strap lined with the same material and secured by a folding clasp, the Ultrathin Tourbillon Onyx – produced in eight pieces in gold and eight in platinum – embodies a timeless elegance, elevated by understated sophistication.