Mother-of-pearl is not a color and cannot be manufactured, which is the whole interest of this dial. F.P. Journe built the Nacre series for his own boutiques, where it is sold on an application basis rather than from stock, and on the platinum Automatique Lune the treatment takes a particular form: a hour ring cut from blue mother-of-pearl surrounds a center of whitened guilloche silver worked in the Clous de Paris pattern, with Arabic numerals in blue set around the ring. Two quite different surfaces therefore sit together on one dial, an organic one out at the perimeter and a machined one in the middle. Everything behind them is the standard Automatique Lune: central hours and minutes, small seconds at 4:30, a large date, the power reserve at 9 o'clock and a moon phase, driven by the automatic calibre 1300.3.
The material comes out of a shell and no two pieces of it are alike, which imposes a constraint most dial decisions do not. Nacre is the iridescent inner layer of certain molluscs, built up in microscopic sheets of aragonite whose spacing happens to fall close to the wavelength of visible light, so the color a viewer sees is produced by interference between layers rather than by any pigment present in the material. That is why it shifts as the viewing angle changes, and why it cannot be reproduced by paint. It also means every dial is different: the banding, the depth of the blue and the direction of the shimmer vary from one shell to the next, and a manufacture working with it accepts that two watches leaving the same bench will not match. Journe restricted the material to the hour ring rather than covering the whole dial with it, which is much the more disciplined of the two choices, and set it against a whitened silver center whose Clous de Paris guilloche is entirely regular and entirely repeatable. The dial therefore contains both the most controlled surface the manufacture makes and the least controllable material it works with, sitting a few millimeters apart from one another. That juxtaposition is the point of the thing.
Setting this watch is a three-position operation, and it is worth walking through properly, because there is more on the dial than a single crown position could reasonably handle. Pushed home, the crown winds the barrel by hand, which most owners will rarely need to do at all since the rotor keeps it fed. Pulled to the first position it advances the date and the moon, and pulled fully out it sets the hands and stops the seconds so the watch can be synchronized precisely. Nothing requires a stylus and nothing requires the caseback to be opened, which sounds unremarkable until you consider that a great many watches carrying a moon phase correct it through a recessed pusher in the case band, needing a tool that is never where it should be. The practical consequence is that a Nacre left unworn for a fortnight can be brought fully back to correct in well under a minute, without anything at all having to be fetched from a drawer first. Behind the crown, the calibre 1300.3 holds 271 parts and 36 jewels, runs at 21,600 alternations per hour on plates and bridges of solid 18K rose gold, and offers around 160 hours of autonomy of which the first 120 are underwritten as chronometric.
Mother-of-pearl carries a certain amount of baggage in watchmaking, and this piece quietly declines to acknowledge any of it. For several decades the material has been used almost exclusively on women's watches, usually across an entire dial, and frequently in combination with a diamond bezel, to the point where its mere presence became a reliable signal of who a given watch was meant for. Journe's use of the material here is deliberately unlike any of that. It appears on a complicated automatic with a large date, a moon phase and a five-day reserve, in a platinum case, sold through boutiques to established customers; and nothing whatever about the surrounding watch codes the way a mother-of-pearl dial conventionally does. The Nacre series applies the same logic across several references in the catalog, and the cumulative effect is to reclaim the material as one worth using for what it actually does optically rather than for whatever it has come to signify commercially. That is a small act of stubbornness, and it is entirely characteristic of a manufacture that has also declined to move its seconds subdial to six o'clock for the sake of convention, and declined to stop making its movements out of solid gold.
This is a watch that has to be seen in person rather than specified on paper, precisely because the dial is not reproducible. No two examples will be alike, and a buyer who cares about the material should look at the actual watch rather than at a photograph or a reference number, since the blue can run from pale and silvery to deep and heavily banded depending on the shell it came from. Boutique distribution on an application basis means these were never simply available to order, and the surviving population is correspondingly small. On the secondary market, mother-of-pearl is the element that needs care: it is a soft, layered material that can craze or lift at its edges if the watch has been stored badly or exposed to heat at some point, and damage of that sort can be neither repaired nor matched. Examine the hour ring closely under magnification and again in raking light before agreeing to anything. Then run the reference's usual checks: the date jumping cleanly at midnight, the reserve indication working across the length of its scale, and the moon advancing correctly through a full cycle.
