Monochrome Watches
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Arnold & Son Perpetual Moon Obsidian

An oversized moon phase, adorned by an impressive Mexican obsidian.

| By Brice Goulard | 3 min read |
Arnold & Son Perpetual Moon Obsidian

While not a new watch, the Arnold & Son Perpetual Moon remains one of the most fascinating moon-phase watches on the market, thanks to its oversized lunar indication – certainly one of the largest currently available. In addition to this prominent astronomical complication, the Perpetual Moon has often been used to display beautifully crafted dials, such as enamel of aventurine. For its 2020 collection, the brand releases its lunar watch with a material rarely seen in watchmaking, with a dial made from Mexican obsidian, resulting in a golden-bronze uneven surface. Meet the Arnold & Son Perpetual Moon Obsidian.

Arnold & Son Perpetual Moon Obsidian

The idea behind this classic from Arnold & Son is simple, the Moon and nothing but the Moon. The A&S Perpetual Moon features one of the largest moon indications to be found in the watchmaking sphere, as our satellite is exposed in full display across the entire upper half of the dial, with a moon disc that measures over 30mm in diameter. On this edition, the colour scheme for the lunar indication is classic, with a guilloché and lacquered blue background on which are set silvered constellations and, the star of the show, an oversized moon, engraved in a realistic way and later rhodium-plated.

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Arnold & Son Perpetual Moon Obsidian

The main update for this year’s edition of the Arnold & Son Perpetual Moon is its dial… and what a striking dial, indeed. The large surface offered by the void space around the moon phase display allows A&S to play with colours, textures and materials. In the present case, the brand has opted for an unusual stone, golden obsidian. This volcanic stone has been mined in Central America 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. Its warm, golden-bronze colour contrasts greatly with the cold blue hue of the moon and the rhodium-plated hands and applied markers.

Arnold & Son Perpetual Moon Obsidian

To match with the colour of the stone dial, the Arnold & Son Perpetual Moon Obsidian is housed in 18k red gold. The case measures 42mm in diameter and 11.4mm in height, with a thin bezel offering an unimpeded view on the dial and the moon indication. Its surface is mostly polished, with stepped lugs featuring a brushed plaquette on the side. For nice colour contrast, the alligator leather is dark blue with silvered stitching, and closed by a gold pin buckle.

Inside the case is a large and powerful in-house movement, the hand-wound calibre A&S1512. Boasting a comfortable 90-hour power reserve, it features an addition moon indication on the backside, used to precisely set the lunar indication. Its decoration is pleasant, with polished and chamfered bridges, circular satin-finished wheels and blued and chamfered screws, with polished heads.

Availability & Price

The new Arnold & Son Perpetual Moon Obsidian is a limited edition of 28 pieces. It retails for CHF 31,900 (excl. taxes). More details at

1 response

  1. Well, it is a beautiful – and very desirable – watch, but no way is the moon disk over 30 mm in diameter: if it were, then it would be three quarters of the diameter of the watch!

    Maybe the cut-out section in which the moon disk is displayed would have a diameter of c. 30mm were it circular.

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