Some watches go beyond mechanical prowess alone to become genuine works of art. With the Exo Tourbillon Skeleton Limited Edition 18, Minerva celebrates its heritage through a creation in which fine watchmaking meets miniature sculpture, Roman history and the symbolism of precious materials. At the heart of an 18-carat rose gold case, a blue and white agate cameo depicts the profile of Minerva, while the skeletonised movement reveals the fascinating architecture of the manufacture’s patented Exo Tourbillon.
On this page
- Minerva, a mechanical heritage in the service of creation
- An agate cameo, a tribute to ancient Rome
- Persian blue, the colour of wisdom and power
- A fluted rose gold bezel, a historic signature
- The Exo Tourbillon, a singular mechanical architecture
- A skeletonised movement where every finish counts
- A presentation box inspired by the caskets of Antiquity
- Eighteen pieces to celebrate Minerva’s watchmaking art
- Technical specifications, Minerva Exo Tourbillon Skeleton Limited Edition 18
- Frequently asked questions
Limited to 18 pieces, this exceptional watch combines rare artisanal expertise with a complication developed by Minerva, in a composition where every detail tells a story. Persian blue, rose gold and references to Antiquity create a singular aesthetic world, in the service of a mechanism whose sophistication is revealed without reserve.
Minerva, a mechanical heritage in the service of creation
Founded in 1858 in Villeret, Minerva holds a special place in the history of Swiss watchmaking. The manufacture has distinguished itself in particular through its expertise in designing mechanical movements and chronographs, as well as through the quality of its hand finishing.
That heritage lives on today in creations that give pride of place to traditional mechanics and uncompromising craftsmanship. The Exo Tourbillon, unveiled in 2010 after three years of development, illustrates this desire to explore new architectures while preserving the fundamental skills of fine watchmaking.
With this limited edition, Minerva adds an artistic and historical dimension to its patented complication. The manufacture’s name, inspired by the Roman goddess of wisdom, the arts and strategy, becomes the common thread of a watch that brings watchmaking engineering into dialogue with the art of the antique cameo.
The result is more than a decorative depiction of Minerva. It is a composition in which stone, precious metal and mechanical movement all contribute to the same narrative.
An agate cameo, a tribute to ancient Rome
The centrepiece of this creation is a blue and white agate cameo set within the open dial. Its profile of Minerva draws on historical depictions of the goddess, notably those used in the manufacture’s early advertisements.
The choice of a cameo points directly to Roman Antiquity. These precious objects, admired for the delicacy of their carving, were collected by the elite and by emperors, including Augustus and Nero. They were as much miniature works of art as markers of wealth, power and refinement.
The cameo adorning the Minerva Exo Tourbillon Skeleton Limited Edition 18 combines several techniques. Its blue agate base is worked using the black polishing method, which produces a particularly refined surface. A second piece, in white agate, is then inlaid, laser-textured, hand-engraved and decorated by a painter specialising in miniatures.
This layering of materials and skills creates a subtle relief, in which the goddess’s profile stands out from its background. Contemporary technology plays a part in the process, but it remains in the service of an art of precision in which the human dimension is still essential.
The cameo thus becomes far more than a decorative element: it is the symbolic centre of the watch and echoes the very identity of Minerva.
Persian blue, the colour of wisdom and power
Persian blue plays a defining role in this edition’s visual identity. It dresses the cameo, the strap and the presentation box, creating chromatic continuity between the watch and its case.
Minerva associates this deep hue with the goddess’s eyes and with the symbolism of European royalty. It also evokes wisdom, diplomacy and the pursuit of peace, all themes traditionally linked to Minerva in Roman mythology.
Blue agate, sometimes nicknamed the “diplomat’s stone”, was reputed to promote clear speech and ease in public speaking. This ancient belief resonates with the attributes of the goddess, whose influence extends to strategy, the arts and reflection.
On the watch, Persian blue plays against 18-carat rose gold and the anthracite tones of the openworked movement. This contrast lends depth to the composition while highlighting the precious character of the cameo.
The Persian blue alligator leather strap, with a semi-matte finish, extends this identity. Its lining, decorated with a Roman frieze, echoes a motif found on the watch itself, while the 18-carat rose gold folding clasp completes the ensemble.
A fluted rose gold bezel, a historic signature
The 44.8 mm case is made of 18-carat 750/1000 rose gold. Its polished surfaces bring out the warmth of the metal and underline the precious character of this creation.
The fluted bezel is a first in the world of the Exo Tourbillon. This element, characteristic of Minerva since 1927, appears here on this complication for the first time. Its regular ridges catch the light and create an aesthetic link between the manufacture’s historical heritage and the watch’s contemporary architecture.
The crown, also in rose gold, bears Minerva’s emblematic arrow. This detail carries the house’s identity right through to the functional elements of the case.
At 15.1 mm thick, the watch has a generous volume, needed to showcase its movement and its sculptural decoration. The domed sapphire crystal, with anti-reflective coating on both sides, makes it easy to observe the open dial and the mechanism unfolding beneath it.
The transparent caseback, set in a rose gold construction, allows the other side of the calibre to be admired. Water resistance is rated at 30 metres, in keeping with the essentially horological and artistic vocation of this exceptional piece.
The Exo Tourbillon, a singular mechanical architecture
While the cameo catches the eye first, the mechanism is the second great spectacle of this creation. The Minerva Exo Tourbillon Skeleton Limited Edition 18 is powered by the in-house M18.69 calibre, a hand-wound mechanical movement developed around Minerva’s patented complication.
What sets the Exo Tourbillon apart is the position of the balance wheel, placed outside the tourbillon cage, above it. The prefix “Exo”, from the Greek, expresses exactly this external arrangement.
This architecture makes it possible to reduce the diameter of the cage and limit the rotating mass, while allowing the use of a large balance wheel. It measures 14.5 mm in diameter and has 18 adjusting screws that contribute to its regulation.
The M18.69 calibre beats at 18,800 vibrations per hour, or about 2.5 Hz, and offers a power reserve of around 50 hours. The tourbillon makes one revolution per minute, which also allows the seconds to be read.
Fine-tuning this assembly demands great precision. Minerva states that the alignment of the balance staff must respect a tolerance of just five microns, or 0.005 mm. This adjustment is carried out by hand at the Villeret manufacture.
The architecture of the balance bridge, held by a single arm, also bears witness to the expertise required to design this watch. The construction must combine stability, precision and visual openness, preserving the integrity of the mechanism while leaving it fully visible.
A skeletonised movement where every finish counts
For this edition, Minerva has extensively openworked the calibre’s structure to reduce the presence of metal and highlight the motion of the tourbillon. The mechanism seems suspended in space, amid fine lines and skilfully arranged voids.
The calibre has 188 components and 19 jewels. Its ruthenium-treated German silver bridges, in an anthracite tone, feature Geneva stripes on both sides and hand-chamfered edges. The gear train wheels receive gilt finishes, while several components benefit from particularly careful frosting and polishing.
One of the most demanding aspects is the treatment of the inward angles. Creating them requires exceptional manual skill, since they cannot be produced by a simple standardised machine operation. Mirror polishing adds a further finish to selected components.
Minerva cites more than 400 hand-polished inner bevels for this architecture. This work helps make the watch an object of contemplation, in which reflective surfaces respond to the openings in the movement.
The tourbillon is surrounded by a gilded rose gold frame decorated with a Roman frieze. The name “Minerva”, engraved at the top of the cage and filled with blue lacquer, extends the watch’s colour palette.
At 4 o’clock, a gilded rose gold plate bears the Roman numeral “XVIII”, a reminder of the limitation to 18 pieces. The number also echoes 1858, the year the manufacture was founded, strengthening the link between this contemporary creation and its historical roots.
A presentation box inspired by the caskets of Antiquity
The experience continues beyond the watch with a presentation box designed in the same historical spirit. Dressed in Persian blue, it is made of walnut and decorated on the outside with a Roman frieze motif.
Its role is not limited to protecting the timepiece. It is designed to double as a jewellery box, a nod to the precious caskets of Antiquity that combined practical function with an expression of refinement.
Inside, a compartment holds a blue watchmaker’s loupe. This accessory invites the owner to observe the details of the calibre, the hand finishing and the miniature carving of the cameo.
The box thus becomes an extension of Minerva’s artistic approach. From the carved stone to the openworked movement, from the rose gold case to the walnut box, every element contributes to the same narrative inspired by Roman Antiquity.
Eighteen pieces to celebrate Minerva’s watchmaking art
The Minerva Exo Tourbillon Skeleton Limited Edition 18, reference 137551, will be produced in just 18 pieces. This rarity matches the level of craftsmanship its creation requires, as well as the singularity of its decoration and mechanical architecture.
The watch brings together several disciplines rarely found in a single creation: agate carving, miniature painting, goldsmithing, the skeletonisation of a complex movement and the hand finishing of fine watchmaking. Added to this is a patented complication whose construction places the balance wheel above the tourbillon cage, giving the mechanism an exceptional visual presence.
Certified by the Laboratoire Minerva 500-hour test, this edition pairs its artistic ambition with a dedicated testing procedure.
With this creation, Minerva does more than celebrate its name and history. It turns its heritage into a horological work in which mythology, ancient art and mechanical precision answer one another. Minerva’s profile watches over the movement, while the tourbillon keeps turning beneath the cameo: a meeting between human time, the motion of the wheels and the permanence of symbols.
Technical specifications, Minerva Exo Tourbillon Skeleton Limited Edition 18
| Reference | 137551 |
|---|---|
| Edition | limited to 18 pieces |
| Movement | Minerva in-house calibre M18.69, hand-wound mechanical |
| Complication | patented skeletonised suspended Exo Tourbillon, one revolution per minute |
| Components | 188 |
| Jewels | 19 |
| Power reserve | approx. 50 hours |
| Frequency | 18,800 vibrations per hour, or 2.5 Hz |
| Balance | screw balance, 14.5 mm diameter, moment of inertia 59 mg·cm² |
| Balance spring | with Phillips terminal curve |
| Functions | off-centre hours and minutes, small seconds at 6 o’clock and seconds indication by the tourbillon |
| Dial | anthracite openworked structure in ruthenium-treated German silver, with blue and white agate cameo depicting Minerva |
| Case | 18-carat 750/1000 rose gold, polished, with fluted 18-carat rose gold bezel |
| Dimensions | 44.8 mm diameter, 15.1 mm thick |
| Crystal | domed sapphire with anti-reflective coating on both sides |
| Caseback | transparent sapphire crystal, with single-sided anti-reflective coating |
| Water resistance | 30 metres (3 bar) |
| Crown | 18-carat rose gold, decorated with the Minerva arrow |
| Strap | Persian blue alligator leather with semi-matte finish, lining decorated with a Roman frieze |
| Clasp | 18-carat rose gold triple folding clasp |
| Certification | Laboratoire Minerva 500-hour test |
Frequently asked questions
Just 18 pieces, under reference 137551. The number, recalled by the Roman numeral XVIII at 4 o’clock, also echoes 1858, the year Minerva was founded in Villeret.
It depicts the profile of Minerva, the Roman goddess of wisdom, the arts and strategy. Made of blue and white agate, it is inspired by the cameos of ancient Rome collected by emperors such as Augustus and Nero.
It is a patented complication, unveiled in 2010, whose balance wheel sits outside the tourbillon cage, above it. This architecture reduces the rotating mass and allows a large 14.5 mm balance wheel.
The skeletonised, hand-wound in-house M18.69 calibre, with 188 components and 19 jewels. It beats at 18,800 vibrations per hour (2.5 Hz) and offers around 50 hours of power reserve.
Its 18-carat rose gold case measures 44.8 mm in diameter and 15.1 mm thick, with a fluted rose gold bezel. It is water-resistant to 30 metres and fitted with a Persian blue alligator strap.
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