Mother of Pearl Dial 25661PT Audemars Piguet Perpetual Calendar

There are probably far fewer than 10 of these: an Audemars Piguet ref. 25661 in platinum with a mother of pearl dial. Within the long march of the QP which brought back complicated watchmaking to Switzerland (famously developed in secret), the 25661 was first to feature a display caseback—which here is quite deserved. 342 were made, of which 37 were in platinum. Alongside salmon and Tuscan, the mother of pearl dials are some of the most desirable AP QPs ever made.

The ultra-thin movement was at time a world record at 3.95mm and developed in secret by lead watchmaker Michel Rochat, founder of the technical department Daniel Golay, and head of service Wilfred Berney for fear that top brass would not spend on complicated movement development in place of quartz. The case was penned by Jacqueline Dimier at a discreet 36mm with downturned lugs. Interestingly, early cases have extruded corrector pushers that stand a bit proud while latter productions such as this example were improved to sit flush. The 25661 features a skeletonized and engraved rotor, while pretty much everything else remains the same.

These dials are not raw mother of pearl, but galvanically bathed to bring forward the pearlescent effect. This lends greens, purples, blues, and teal altogether. You’ll also see a different dial made of a blue galvanic treatment which lends a sky blue effect to the whole thing. Many dials don’t survive intact. We’ve seen just a few in white metal in total.

Any mother of pearl 25661, 25736, or 25657 (etc.) is easily one of the most captivating examples of the 'holy trinity' post-quartz QP watchmaking. They hark back to the 90s largely, the last point where there was a sense of daring in many AP model lines. Mother of pearl is just one of many beautiful pieces from this time. This one has box and papers as well (Fun fact, the last one we had a few years ago included in its set a VHS tape describing the watch). It is simply beautiful, and quite unlike anything AP make today.

This example has a strong case with defined hallmarks and lug-side vertical brushing (which you always need to see). The watch has its platinum pin buckle, box, and warranty papers dating to 1995. It comes from a well-regarded Florida retailer.