Arnold & Son’s Ultrathin Tourbillon Onyx blends the beauty of black onyx with the elegance of an ultra-thin flying tourbillon for a truly captivating haute horlogerie creation!
Arnold & Son have once again shown that high watchmaking does not always need to be extravagant or loud to make an impact. With their brand new Ultrathin Tourbillon Platinum Onyx, unveiled during Watches and Wonders 2026, Arnold & Son takes one of watchmaking’s most elegant complications and gives it a beautifully luxurious presence, pairing a deep black onyx dial with a slim platinum case for a look that feels both bold and refined. It is the kind of timepiece that draws you in through its simplicity, yet keeps your attention through its intricate and thoughtfully executed design.
There is a real sense of balance in the design, with every element feeling considered rather than overworked. This allows the watch to come across as sophisticated and expressive, without losing the refined character that Arnold & Son do so well. It is the sort of release that reminds you true luxury can still feel understated.
What makes this a compelling release is how Arnold & Son has balanced the visual beauty of the dial’s two core elements while still showcasing the brand’s serious watchmaking pedigree. The maison has introduced two versions of this Ultrathin Tourbillon Onyx, one in 950 platinum and the other in 18-carat 5N red gold, with each offering its own distinct personality.
A Tale Of Beauty In Motion
The case of the Ultrathin Tourbillon Onyx models is all about understated luxury. Both the 950 platinum and 18-carat 5N red gold versions measure 41.5mm in diameter and just 8.40mm thick, giving the watch a slim and elegant profile that sits perfectly in tune with its refined character. The smooth curves of the case and lugs help define this elegance, while the slim bezel opens up the dial beautifully and enhances the watch’s overall presence on the wrist.
While the platinum model delivers a sharper, more contemporary contrast against the black onyx dial, the red gold edition, in my opinion, brings a richer and warmer elegance to the overall design. In both cases, Arnold & Son have managed to create a timepiece that feels luxurious and visually appealing, while still keeping the focus firmly on the mechanical complication at the heart of the watch.
The dial is, of course, the central highlight of this timepiece, more specifically, the material it is crafted from. Arnold & Son have used black onyx for both the main dial and the off-centre concave hours-and-minutes dial at 12 o’clock, creating a beautiful monochromatic look for the platinum model that instantly feels elegant and full of character. The red gold edition, however, has to be my personal favourite, as the way the gold contrasts against the deep black onyx dial is simply stunning.
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.
Arnold & Son on the onyx dial of the Ultrathin Tourbillon
Arnold & Son have also broken new ground with the use of this material. While it is certainly not the first time that onyx has been used on an Arnold & Son timepiece, they have ventured into uncharted territory here by giving the material a matt satin finish. Complex in its execution, this treatment gives the dial a softer and more understated appearance, allowing the black onyx to showcase a different character compared to the usual high-polished aesthetic. It adds another layer of visual appeal to the timepiece, proving that even with a material as bold as onyx, Arnold & Son can still find new ways to elevate its beauty.
There is a richness to the red gold case that makes the black onyx appear even deeper and more luxurious, giving it, as mentioned earlier, a warmth and visually captivating presence. While the platinum model leans more into sharp contrast and modern elegance, the red gold edition feels slightly more expressive, offering a look that is both luxurious and beautifully balanced at the same time.
Then, at 6 o’clock, we have the mechanical masterpiece that is the flying tourbillon. A complication that I personally will never tire of, Arnold & Son have put their own spin on this mechanical marvel by integrating a stylised sextant. For those who may not know, the sextant is a subtle yet meaningful nod to John Arnold’s legacy in marine chronometry, giving the flying tourbillon an added layer of storytelling beyond its technical beauty.
Beneath The Surface, A Golden Work Of Art
Powering these latest Ultrathing Tourbillon Onyx models is Arnold & Son’s in-house A&S8300 manual-winding calibre, a movement created to perfectly capture the elegance and technical ambition of the collection. At just 2.97mm thick, it is one of the smallest tourbillon movements on the market, and even with how thin it is, it still delivers the level of performance expected from a haute horlogerie timepiece. Operating at 3Hz (21,600 VpH), it delivers an impressive 100-hour power reserve!
Through the transparent caseback, the calibre showcases the exceptional movement finishing standards of Arnold & Son. From the radiating Côtes de Genève on the main plates, chamfered edges, snailed ratchet wheels, polished blued screws, to the 3N yellow gold flying tourbillon bridge that has been hand-engraved with plant motifs (inspired by John Arnold’s historic pocket watches), every detail adds to the visual beauty of the movement and timepiece. It is a beautifully executed display of traditional finishing and mechanical artistry, giving the reverse side of the watch just as much appeal as the beautiful dial on the front.
Initial Thoughts
The Ultrathin Tourbillon Onyx may seem like a simpler release from Arnold & Son, but it is still a timepiece that is executed to a degree of sophistication, blending artistic beauty with serious watchmaking. What I love about the dial is that, despite its minimalism, it still manages to feel highly distinctive. The off-centre display creates a nice asymmetrical touch, while the large flying tourbillon aperture below adds motion and visual appeal without overwhelming the overall layout.
Arnold & Son have done a great job of letting the natural beauty of the onyx take centre stage, using the dial not just as a backdrop for telling time, but as a key part of the watch’s identity. Combined with the elegance of the beautiful propotioned, polished, elegant case in either 950 platinum or 18k 5N red gold, the Ultrathin Tourbillon Onyx feels like a complete expression of Arnold & Son’s watchmaking DNA.
These new timepieces, for me, are a more simplistic design from the brand, but one that still showcases their artistic and mechanical expertise, all beautifully wrapped in one refined package!
Arnold & Son – Ultrathin Tourbillon Onyx
Reference & Specifications
| Feature | Specifications |
|---|---|
| Reference | Platinum (1UTBX.Z03A.C1375C), Red Gold (1UTBR.Z02A.C1375R) |
| Dimensions | 41.5mm x 8.40mm thick |
| Case | 950 Platinum or 18K 5N red gold with polished surfaces. |
| Crystal | Domed sapphire with an anti-reflective coating on both sides |
| Dial | Black Onyx with matt satin finishing. Offcentre concave time dial at 12 o’clock, flying tourbillon at 6 o’clock. |
| Caseback | Black Onyx with matt satin finishing. Off-centre concave time dial at 12 o’clock, flying tourbillon at 6 o’clock. |
| Movement | Manual-wound in-house calibre A&S8300, beating at a frequency of 3Hz (21,600 VpH) |
| Functions | Hours & minutes |
| Power Reserve | 100 hours |
| Water Resistance | 30 metres (3 ATM) |
| Strap | 18K White gold with alternating polished gadroons and horizontal brushed surfaces |