Arnold & Son Ultrathin Tourbillon Onyx Platinum

The Ultrathin Tourbillon Onyx Edition by Arnold & Son is a study in contrast, combining extreme mechanical refinement with the deep, enigmatic beauty of natural stone. Offered in limited edition of just eight pieces each in 950 platinum, the all-new watch presents a strikingly minimalist aesthetic defined by its rich black onyx dial and ultra-slim profile.

Measuring 41.5 mm in diameter and only 8.3 mm thick, the case is designed to maximize the visual impact of the dial. The onyx, carefully cut and polished from a single disc, reveals a deep, uniform black tone that serves as a dramatic backdrop for the flying tourbillon at 6 o’clock. This aperture exposes the constantly rotating cage, whose hand-finished architecture contrasts beautifully against the dark stone surface. A smaller, matte-finished onyx subdial for the hours and minutes adds further texture, introducing a subtle interplay between polished and satin surfaces.

Powering the watch is the in-house A&S8300 calibre, a hand-wound movement measuring just 2.97 mm in thickness. Despite its slim construction, it delivers a robust 100-hour power reserve, aided by technical refinements such as a variable-inertia balance and an optimized tourbillon cage. The movement’s finishing is equally impressive, featuring radiating Geneva stripes, hand-bevelled edges, circular graining, and polished screws, all visible through the sapphire caseback.

The tourbillon itself carries historical significance, incorporating design elements inspired by John Arnold’s marine chronometers, including a sextant motif and anchor-shaped counterweight. These details pay tribute to the brand’s heritage while reinforcing the watch’s narrative depth.

Paired with a black alligator leather strap, the Ultrathin Tourbillon Onyx Edition balances visual restraint with technical sophistication, resulting in a timepiece that is both elegant and mechanically compelling.