Monochrome Watches
An online magazine dedicated to fine watches

The Dazzling Neon Glow Of The Arnold & Son Luna Magna Ultimate II

A mesmerising take of the Luna Magna, glowing with the neon-turquoise light of exotic Paraiba tourmalines and diamonds.

| By Rebecca Doulton | 3 min read |

Arnold & Son already caught our attention with its impressive Luna Magna 3D moon phase when it was released in 2021. Touted as the largest 3D moon phase ever fitted inside a wristwatch, the Luna Magna’s rotating aventurine and marble 12mm moon exerted its gravitational pull to great effect. For the third edition of Geneva Watch Days, Arnold & Son presents a mesmerising take on the Luna Magna glowing with the neon-turquoise light of exotic Paraiba tourmalines and diamonds. Limited to eight pieces, the moon has never looked as enticing as the gem-encrusted globe animating the Luna Magna Ultimate II.

Neon-bright turquoise Paraiba tourmalines are one of the most sought-after gemstones and were only recently discovered in the 1980s in the Brazilian state of Paraiba. The dramatic incandescent glow that lights up the stone from within is unlike any other gemstone. Combined with the rarity of the stone (1 Paraiba tourmaline mined for every 10,000 diamonds), you can imagine the stir these gemstones have created on the jewellery scene. And although Arnold & Son has always been into dramatic displays, I don’t think anybody covering the watch scene saw this one coming.

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Sharing the same specifications as the Luna Magna we covered last year, the effect couldn’t be more different. For starters, the 44mm diameter white gold case is embellished with 7.62 ct of high-quality diamonds. The bezel is set with two rows of invisible-set diamonds that dip over the edge to capture the light like an open prism. The sparkling diamond frame reveals the glittering greenish-blue dial made of pure ruthenium crystals designed to capture the same colour as the Paraiba tourmalines on the moon. Ruthenium is found in platinum mines but much rarer than platinum. Transformed into crystals and dyed to match the Paraiba tourmalines, the ruthenium crystals on the dial plate have become a unique feature of Arnold & Son watches. The traditional dial at noon with classical Roman numerals and openworked blued hands – a nod to the aesthetics of John Arnold’s marine chronometers – is made from opal.

Rotating in the large aperture at 6 o’clock is the dazzling 3D white gold moon. Entirely paved with precious gemstones, the 161 brilliant-cut diamonds represent the illuminated side of the moon, while 161 stunning Paraiba tourmalines represent the portion in shadow.

Astronomical accuracy is guaranteed by the precision moon phase complication developed by Arnold & Son. Taking into account the 29 days, 12 hours, 44 minutes, and 2.8 seconds of a complete lunar cycle, Arnold & Son’s precision complication ensures that if the watch were kept wound, it would only need a one-day adjustment in 122 years. However, there is a practical way to correct the moon phases directly at the crown.

The reverse side of the case offers a generous view of the A&S1021 calibre, a hand-wound movement beating at 21,600vph/3Hz with a robust 90-hour power reserve. What is particularly beautiful is that you can see the other side of the spherical moon on the caseback (framed by a pink ring), which also explains why there is a domed sapphire crystal over the movement. Just above the sphere is a more accurate indicator of the eight phases of the moon (New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter and Waning Crescent). The movement has a diameter of 37.6mm and, including the 3D moon, the height is 12mm; without the moon, it measures a slim 4.75mm. Like all A&S movements (which are made by La Joux-Perret, part of the Citizen Group and sister company of Arnold & Son), the finishing is traditional with Geneva stripes radiating from the centre of the movement, blued, chamfered screws with polished heads and circular graining with a satin finish on the wheels.

The Arnold & Son Luna Magna Ultimate II comes with a hand-stitched lagoon-blue alligator leather strap with a raspberry pink alligator lining and a white gold pin buckle set with 26 baguette-cut diamonds. It is a limited edition of eight timepieces and retails for CHF 199,000 (incl. tax). For more information, please visit

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