Blue shell against platinum is the cold version of the Nacre dial and the one that photographs least like it looks. Mother of pearl reads flat in pictures and moves in person, and blue shell in particular shifts between gray, green and something closer to silver depending on the angle. The house pairs blue with platinum and pink with rose gold, and has never mixed them. This is the Automatique Lune in that first combination, with a whitened guilloche silver center inside a blue shell ring, from the second generation of the model. Nacre has been a boutique-only program since 2012, and this execution was discontinued in 2024. It was offered at 40 and 42 mm, nothing was changed behind the dial, and there was never a declared edition size.
Platinum at 40 or 42 mm and 10.7 mm deep, polished, with the knurled crown the reference carries throughout. The dial is built in two parts. At the center is whitened guilloche silver, worked with the Clous de Paris pattern the model has used since the 2019 revision, and around it a ring of blue mother of pearl. Shell has to be cut, ground and fitted rather than finished like metal, and in a ring format it has to hold an even thickness across a narrow band, which is why the material is rare in this position and common as a full disc. Against a platinum case the blue reads cooler than it would in gold, and the whitened center keeps the middle of the dial neutral so the shell is the only color present. The date opens at the top on two discs, the moon sits low on the left behind sapphire, and the seconds turn at half past four. Blued steel hands cross the face, and against a blue ring they agree rather than contrast, which is one reason this execution looks calmer than the pink one. The standard strap is the usual fitting. Both case sizes use the same dial layout, so the 42 mm carries a broader shell ring and the 40 mm a narrower one, and the difference in how much of the material is on show is larger than the two millimeters would suggest.
Behind the dial the watch is unchanged, as every boutique execution is. The automatic base is the Octa introduced in 2001, wound through a 22K gold rotor mounted off to one side and turning in a single direction on a self-locking ball bearing arrangement, chosen so that small wrist movements are converted into winding rather than wasted. Most of the movement is visible through the sapphire back because the rotor does not sit over it. The date is instantaneous and made from two discs, the moon advances one notch at the same moment, and the small seconds run continuously. Every indication is corrected from the crown, in different positions, with nothing hidden in the lugs. On a shell dial that arrangement has an additional benefit, since a watch that never needs a tool near the case is a watch whose dial is less likely to be disturbed. Journe applies the same constraint across the collection and it is one of the least discussed reasons his complicated watches survive handling well. The moon is the only indication that ever drifts far enough to need attention, and that takes years to happen. In ordinary use the watch asks for nothing beyond being worn. The date takes care of itself in every month of thirty-one days and needs a correction at the end of the shorter ones, which is the standard behavior of a large date without an annual calendar behind it.
Boutique programs at this house divide into three: the black dials that began in 2007, the Black Label watches in platinum that followed, and the Nacre pieces from 2012. Each exists for the same reason, which is that Journe owns his dial factory and can differentiate a watch at the dial without touching the movement. Nacre is the only one of the three that depends on a material the house cannot manufacture. Shell has to be sourced, matched and worked, and the supply constrains how many dials can be made in a way that a color finish does not. The Automatique Lune Nacre paused, returned in 2021 alongside the revised dial and the larger cases, and closed in 2024, while the Octa Automatique Reserve Nacre stopped in 2016 and was never revived. That leaves the moon phase as the longest-running Nacre reference and the one most likely to be encountered. Platinum with blue shell is the configuration most collectors picture when the program is mentioned, and it has always been the harder of the two to find. Part of that is simply how the pairing was received. Blue shell against a white metal case photographs better than pink against gold and reads as the more serious of the two, so it was ordered more often and kept more often, which leaves fewer of them moving.
Discontinued boutique executions are bought on condition rather than on availability, and with a shell dial the condition that matters is the dial itself. Mother of pearl marks, and it cannot be refinished or matched, so an example with an undisturbed ring is worth holding out for. Beyond that the watch is a standard Automatique Lune and behaves like one, which means it can be worn without ceremony despite the material. Platinum makes it heavy and the blue keeps it formal, so it reads as the dressier of the two Nacre versions. The 42 mm shows more shell and the 40 mm is the more traditional proportion. Papers naming the boutique execution are useful, since nothing on the case identifies it and a shell ring is the kind of detail that gets described loosely in a listing. Shell rings and shell dials are not the same thing, and a description that says mother of pearl without specifying which is describing two different watches at once. Checking the dial specification before committing is worth the effort.
