There are watches with moon-phases and then there is the Arnold & Son Perpetual Moon, the only timepiece in which the lunar complication truly dominates the dial, relegating even the central hours and minutes to secondary status. The Swiss luxury watchmaker with British roots, named for 18th-Century English chronometer pioneer John Arnold, introduced the model in 2013 to instant acclaim, and the latest version, called the Perpetual Moon Obsidian, showcases an ancient material rarely found in watchmaking.
The watch’s 42-mm case, made of 5N 18k rose gold, frames a dial made of golden obsidian from Mexico, a semi-precious volcanic stone that has been mined throughout Central America since the dawn of history and was used in religious ceremonies by pre-Columbian civilizations. Its shimmering, bronze-like surface is derived from its chemical composition — which includes a high level of silica content that renders it both hard and shiny — and its specific crystallization. The sword-shaped hands are rhodium-plated and the wedge-shaped hour appliqués are in diamond-polished white gold.
Also rhodium-plated is the timepiece’s signature attraction, the large, ultra-realistic hand-engraved moon disk, which waxes and wanes against the backdrop of a blue-lacquered silvered-star-dappled sky inside the vast, semicircular aperture in the upper half of the dial. In keeping with the ethos of the brand and its history of chronometry, this lunar display is not only eye-catching but also super-accurate, deviating from the actual lunar cycle by just one day every 122 years.
Fully developed and manufactured in-house at Arnold & Son’s atelier in La Chaux-de-Fonds, Switzerland, is the movement beating inside the case, the hand-wound Caliber A&S 1512. Aside from the highly accurate double moon-phase complication (a second display is visible on the back), the movement is notable for its single large barrel, rotating at 21,600 vph or 3 Hz, which provides a lengthy power reserve of 90 hours. It’s also a visual feast of high-horology finishing, with center-radiating cotes de Geneve adorning the mainplate, blued screws with polished heads, circular satin-finished wheels and polished and chamfered bridges.
The Arnold & Son Perpetual moon Obsidian is limited to just 28 pieces, all mounted on blue alligator leather straps with silver-colored stitching to echo the moon-phase’s starry sky background and fastening to the wrist with 18k rose gold pin buckles. It is priced at 31,900 Swiss francs, or around $35,000.
|Arnold & Son Manufacture La Joux-Perret S.A.,
Boulevard des Éplatures 38, 2300 La Chaux-de-Fonds, Switzerland
|Hours, minutes, moon-phase indications
|Caliber A&S 1512, manually wound, 27 jewels, frequency = 21,600 vph (3 Hz), 90-hour power reserve in single barrel, diameter = 34 mm, thickness = 5.35 mm
|18k rose gold case, domed sapphire crystal with nonreflective coating on both sides, sapphire caseback, water-resistant to 30 meters
|Bracelet and clasp:
|Blue alligator leather strap, hand-stitched with silver thread, 18k gold pin buckle
|Diameter = 42 mm, height = 11.43 mm