Arnold & Son - ARNOLD & Son Perpetual Moon Obsidian 1GLAR.Z01A.C154A
Arnold & Son - ARNOLD & Son Perpetual Moon Obsidian 1GLAR.Z01A.C154A

ARNOLD & Son Perpetual Moon Obsidian 1GLAR.Z01A.C154A

Arnold & Son | 39'300 € Tax inc.

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The shifting moon

With its XXL moon, the Perpetual Moon is ruled by Selene, the goddess of this celestial body. Arnold & Son presents a limited edition of 28 pieces featuring this distinctive complication, adorned with an extraordinary material rarely seen in watchmaking. With a dial made from Mexican obsidian, this timepiece appears to be bathed in bronze moonlight. The stone is reflected in the large rhodium-plated moon and the perfectly polished hour-markers. The result is an interplay of reflections, vibrations and warmth that echoes the light of Earth’s satellite. 


Showcasing one of the largest moons to be found in the watchmaking sphere, the Arnold & Son Perpetual Moon Obsidian stands out for the size of its complication and the aesthetic approach employed by the resolutely British Swiss brand. Housed in a 42 mm red gold case, beneath a rarely seen golden obsidian dial, is its hand-wound calibre A&S1512, offering a precision double moon phase display. 



On the movement side, a hand display allows for extremely fine adjustments. On the dial side, a large moon disc occupies almost the entire aperture, presented in a vast window with a round cut-out that allows the changing faces of the moon to be admired. The realistic depiction is crossed by shadows and areas of relief to add to its presence. 



In the exterior details, Arnold & Son has taken this approach even further. The moon is only visible because it reflects the light from the sun. In the same way, the light brings the Perpetual Moon Obsidian to life with its shimmering reflections. 


A golden heart

From Mexico, the Manufacture sourced of one of the oldest and most intriguing stones: golden obsidian. This volcanic stone has been mined in Central America since time immemorial and was used in particular in the religious ceremonies of pre-Columbian civilisations. Obsidian has a very high silica content, making it a hard and shiny material. 

Golden obsidian owes its shimmer to the semi-precious stone’s chemical composition and its specific crystallisation. Its bronze hue extends far beneath the surface, right into the heart of the material. Despite the minute amount used for the dial, it still produces a glistening effect, reflected in turn in the hands and hour-markers.



Arnold & Son selected cool shades to contrast with the stone. The moon and hands are rhodium-plated and the hour-markers are made from diamond-polished white gold. Together, these choices enhance the reflections of the golden obsidian and the red gold of the case. To complete this contrasting interplay of warm and cool tones, the brand chose a blue alligator-leather strap with visible silver-coloured topstitching. 



Like all the movements used by Arnold & Son, the calibre A&S1512 was entirely developed, produced, decorated, assembled, adjusted and cased up in the brand's manufacture in La Chaux-de-Fonds. This calibre is based on a double barrel with an oscillation frequency of 3 Hz, giving a 90-hour power reserve. Last but not least, the moon phase display of this movement will remain accurate for 122 years before deviating from the actual lunar cycle by one day.

Technical specifications

Functions Hours, minutes, moon-phase indicator, 

second moon-phase indicator on the back 



Calibre A&S1512, hand-wound mechanical

Jewels 27

Diameter 34 mm

Thickness 5.35 mm

Power reserve 90 hours 

Frequency 3 Hz / 21,600 vph

Finishes main plate: rhodium-plated, Côtes de Genève stripes radiating from the centre 

bridges: polished and chamfered 

wheels: circular satin-finished

screws: blued and chamfered, polished heads 

rhodium-plated and circular-grained moon-phase indicator


Dial stone: golden obsidian

sky: blue lacquered guilloché, silvered constellations

moon: engraved rhodium-plated disc



Material 18-carat red gold (5N)

Diameter 42 mm

Thickness 11.43 mm 

Crystal Domed sapphire with an anti-reflective coating on both sides 

Case back Sapphire crystal 

Water-resistance 30 m /100 ft



Material blue alligator leather hand-stitched with silver-coloured thread 

Buckle pin buckle, 18-carat red gold (5N) 


Reference 1GLAR.Z01A.C154A


Limited edition 28 timepieces


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