Mother-of-pearl is one of only three grounds a yellow gold buyer shares with the rest of the range. Seven of the ten dials offered on this case exist on yellow gold and nowhere else, which makes the metal unusually self-contained, and the exceptions are the grounds that carry no color of their own: white, the fully paved dial and this one. What makes the shell interesting on gold specifically is that it does not stay neutral. Mother-of-pearl transmits light as well as returning it, so the metal underneath and the metal around it both feed into what the eye sees, and the same dial that reads cool and faintly green on a platinum case reads warmer and creamier here. It is the one ground in the roster whose appearance is partly determined by the case it was fitted to.
The material is the inner layer of a shell, cut into a slice thin enough to serve as a dial and laid over a base rather than applied as a finish. Its structure is a stack of microscopic platelets that break light into components as it passes through them, which is why the surface never holds a single value and shifts between white, cream and pale green as the wrist turns. Each slice carries its own figure, bands and swirls running at whatever angle the cut happened to catch, so no two of these dials are alike in the way two lacquered dials would be. The markers are set into gold surrounds with baguette-cut stones at six and nine, and on a warm case that gold does something different from what it does on a cool one. Rather than introducing the only warm element, it links the dial to the case, so the stones read as belonging to the watch rather than as sitting on top of it. The case is 36mm in yellow gold, the bezel is set with diamonds around its full circumference, and the President bracelet closes the composition in polished three-piece links. The gold surrounds are also what makes the arrangement work at a distance. Shell returns light unevenly across its surface, so a bare stone set into it can land against a bright patch and briefly disappear, while a raised gold edge catches light at a different angle from the ground beneath and holds its outline regardless of what the material is doing.
Every opening cut into a shell dial removes material that was chosen for its figure, which is a consideration the flat grounds never face. The Day-Date needs two: a wide arc at twelve for the day written out in full rather than abbreviated, and a window at three for the date. Both are fixed in position across the whole model, so the slice has to work around them rather than the layout accommodating a particularly good piece of shell. The openings are framed because an unframed edge would show the laminate in section, and the frames also close off the point where the figure is interrupted. Both discs jump instantaneously at midnight rather than drifting through the preceding hour, which on a dial with this much activity keeps the two windows from ever showing a fragment. The movement runs roughly seventy hours off a full wind. Nothing else on the watch asks for attention, and on a ground supplying this much of its own, that is the right amount. Eight grounds sit at this reference and mother-of-pearl is one of two listed in more than one marker arrangement, the framed set here and a version taking ten baguette-cut stones. The other six grounds come one way each, and only three of the eight can be had without stones at all.
Mother-of-pearl set with diamonds reaches all four case metals and both case sizes, one of only three grounds in the model that does. The marker treatment is where the reach ends. At 36mm both arrangements are offered on every reference, this one with gold surrounds and stones at six and nine, and a second with baguettes running the whole way around; at 40mm the gold-framed version disappears entirely and the all-baguette dial is the only mother-of-pearl there is. Within yellow gold at this size the field is three references, 128238 with a fluted bezel, 128348RBR, which also splits on the bracelet, and this one, all carrying identical dials. So a buyer working through this ground has six configurations at the smaller size across the three bezels and two arrangements, and a single arrangement waiting if the decision moves to 40mm. That asymmetry is worth knowing before a diameter gets chosen on the strength of a wrist measurement. The three universal grounds behave quite differently from one another despite sharing that reach. White is a manufactured finish and looks the same on every metal it is fitted to. The paved dial is an assembly of stones and also looks the same everywhere. Mother-of-pearl is the only one of the three that changes with its surroundings, which makes it universal in availability and specific in appearance, an unusual combination and the reason it is worth seeing on the metal before committing to it.
Mother-of-pearl on yellow gold is the configuration for a collector who wants a warm watch that is not a monolithic one. Champagne and green ombre commit the dial to the same temperature as the case; the shell keeps changing its mind, going pale and cool in one light and warm in another, so the watch never settles into a single reading. The gold marker surrounds are what keeps that instability from becoming a legibility problem, holding the hour ring visible while the ground moves underneath it. It is also the ground least likely to be duplicated, since the figure in each slice is specific to it, and two examples of this exact reference will not carry the same dial. For a buyer who already owns a yellow gold Day-Date with a conventional ground, this is the one that will not read as a second version of it. That counts for more on this metal than on any other, since the yellow gold roster repeats itself more than the rest of the range does.
