The resonance principle has fascinated watchmakers for centuries, and Armin Strom has made it their calling card. With the Dual Time GMT Resonance Aventurine (ref. ST26-DT.CT), the Biel/Bienne independent takes that signature complication and dresses it in one of the most evocative dial materials in contemporary horology.
The Dial: A Captured Universe
Aventurine is not a mineral in the strict geological sense. It is a glass-based material produced through a centuries-old Venetian process, where copper or other metallic particles are suspended within the glass melt and then cooled slowly to crystallise into sparkling inclusions. The result here is a dial that shimmers with gold flecks against a deep blue-black ground, evoking an astronomical map rather than a watch face. Armin Strom pairs it with black azurage chapter rings, which create a subtle visual boundary between the two time-zone sub-dials and the open movement architecture surrounding them. Applied rose gold-coloured coated polished indexes sit cleanly on the aventurine surface, providing legibility without overpowering the material’s natural drama, and polished and blackened steel day/night discs complete each sub-dial, offering a practical complication in an elegant frame.
Calibre ARF22 and the Science of Resonance
Calibre ARF22 is an entirely in-house design, developed and produced in Biel/Bienne, and it runs on a principle that puts Armin Strom firmly in a category of its own. The movement uses a patented resonance clutch to synchronise two independent regulating organs, allowing both balance wheels to oscillate in sympathy with each other. This sympathetic coupling does not just look extraordinary through the open-worked architecture; it actively improves chronometric stability by dampening the effects of external shocks on either balance. The ARF22 beats at 3.5 Hz (25,200 vph), carries 231 components across 40 jewels, and offers a 42-hour power reserve from its manual-winding mechanism. Its dimensions are 34.15 mm in diameter by 4.92 mm thick, a remarkable achievement given the architectural complexity of the two regulating trains it houses.
Finishing on the ARF22 reaches across every surface visible through the sapphire crystals on both sides of the case. On the dial side, the mirror-polished balance bridge, dressed with hand-bevelled edges, draws the eye immediately, its steel surface playing in direct contrast to the warm rose gold-coloured mainplate below. Rhodium-coated and steel components introduce a cooler metallic grey tone throughout the architecture, and hand-polished bevels, black-polished elements, circular graining and perlage texture the overall composition with genuine variety. Flip the watch over and the movement reveals Côtes de Genève on the gear-train bridges, which echo the rose gold tone of the dial side to build a cohesive visual dialogue across both faces. Crucially, Armin Strom assembles each watch twice during production, checking both mechanical precision and finishing quality at every stage.
The Case: Restrained Architecture
The case measures 39.00 mm in diameter with a lug-to-lug of 44.50 mm and a height of 9.05 mm, proportions that keep the watch wearable despite the mechanical complexity inside. Armin Strom chose stainless steel for the case material, a deliberate choice that lets the aventurine dial and rose gold-coloured movement components read as the warm accents, rather than competing with a precious metal case. Both the sapphire crystal and the caseback carry anti-reflective treatment to maximise visibility of the dial and the movement, and the watch offers water resistance to 5 ATM. A matte grey alligator strap with grey stitching and a stainless steel pin buckle complete the package, keeping the overall tone cohesive and contemporary.
A Limited Expression Worth Understanding
The Dual Time GMT Resonance Aventurine is a limited edition of just 15 pieces, which reflects Armin Strom‘s commitment to artisanal, low-volume production rather than a marketing exercise. At CHF 105,000, it sits in the upper tier of independent horology, but it brings with it a genuine patent in the resonance clutch, fully in-house production, and a dial material that no amount of lacquer or printing can replicate. If you want to wear a working demonstration of one of horology’s most fascinating physical principles, framed in a material that looks like a fragment of the night sky, this is the watch that makes that argument most compellingly.
