Black mother-of-pearl is the most confined ground the collection makes. It appears on six references, every one of them 31 mm, every one of them containing yellow gold, and every one carrying the same single arrangement of diamonds in gold settings with no numeral among them. One diameter, one metal family, one treatment. Nothing else in the current range is narrow on all three axes at once: the paved dial reaches three sizes, aubergine reaches three and changes metal, and even the oversized VI spans three metal families. This variant is one of the six, in a case of steel and yellow gold, under a fluted bezel, on an Oyster bracelet.
Black shell is a different material from the white version and behaves differently under light. The nacre is dark rather than pale, so the refraction that produces pale blues and greens on a white disc instead produces deep greens, purples and bronzes that emerge from something close to black as the wrist turns. It is the only ground in the collection where the color is hidden inside the dark rather than laid across a bright surface, which means the watch reads as a plain black dial in most conditions and discloses itself only in direct light. The settings holding the hours sit in gold collets and read at full strength against it, since a dark shell gives back almost nothing of its own. The gold of this construction sits in the fluted bezel, fluting never being cut into steel, and the case sides, lugs and bracelet are steel throughout. There is a further quality to a dark shell that only becomes apparent over long wear. Because the color is held inside the material rather than applied to it, the dial does not fade or shift the way a lacquered surface can, and the effect it produces at ten years is the effect it produced on the first day. What changes is the owner familiarity with it: the conditions under which the greens and bronzes appear become known, and the dial stops being unpredictable and starts being anticipated. Very few watches reward that kind of attention because very few have anything left to disclose after the first month.
The movement is built to the 31 mm case, self-winding, holding close to 55 hours away from the wrist where the 36 mm references reach roughly 70, the difference being barrel volume in a physically smaller movement. The plate is pierced at each hour position for the settings and nowhere else, which matters more on shell than on metal because the disc is bonded to the plate across its whole area rather than seated at its edge, so it follows any deviation beneath it exactly. On a dark ground that shows as a change in tone rather than as a shadow. The date sits at three under its magnifying lens, its aperture cut through the shell and finished at the edge, and the crown screws home when the watch is not being set. The aperture presents the same difficulty here as on the white version of the material and one more besides. Cutting a window through laminated shell without chipping the edge is exacting on any disc, and on a dark one the finished edge is harder to conceal, since a pale shell diffuses light along the cut while a dark one shows it as a bright line. The tolerance is correspondingly tighter, which is one plausible reason the ground is offered on so few references and never in a larger case where the aperture would be proportionally bigger.
Why the ground is held this tightly is not recorded anywhere, and the shape of the restriction is more suggestive than any single fact about it. White shell reaches every case material but plain steel and every size from 28 mm to 40; black shell reaches one size and one metal family. The two are the same material worked the same way and the collection treats them as entirely different propositions. A buyer who wants a dark shell dial has six references to choose between, all at one diameter, and no route to the ground at any other size in any other metal. Whether that is scarcity by intention or simply a design that was never extended is not something the catalogue will settle. What can be said is that the restriction has held across the whole of the current range rather than being relaxed at any point, and that a ground confined this precisely tends to stay confined. A buyer weighing it should assume the six references are the whole of it rather than the beginning of something wider. Among the arrangements offered on this reference it is also the one whose interest stays entirely private to its owner, which is a specific thing to want from a watch and not a common one.
The argument for this configuration is scarcity of a particular kind. This is not a limited edition and nothing about it is announced, but the ground occupies a smaller corner of the collection than anything else currently made, and it does so quietly, in a steel and gold case with a plain ring of settings and no numerals. Collectors who choose it are generally the ones who noticed how few places it appears. The Oyster keeps the watch flat and unassuming, which suits a dial that reveals itself only under direct light. Among the arrangements offered here it is the one that will be hardest to replace and the least likely to be recognized for what it is. That combination suits a particular temperament: someone who wants the rarest thing on the reference and specifically does not want it to be visible as such. Nothing about the watch announces that the ground is scarce, and a viewer who does not already know the range will read it as a black dial in a steel and gold case, which for most owners of this configuration is exactly the intended outcome.
