E meralds, rubies and sapphires are not enough to mark the 50th anniversary of Royal Oak. Thus, Audemars Piguet included seven other precious stones rarely seen in Haute Horlogerie for commemorative timepieces.
Instead of iridescent colours on one single watch, the Swiss brand evokes the rainbow through 10 Royal Oak Selfwinding timepieces, sized at 41mm, and each decorated with gemstones in a vivid red, yellow, green, blue, purple, pink or orange hue.
The milestone is actually celebrated with a double rainbow, as there's a second set of 10 smaller high-jewellery models with a diameter of 37mm.
The colours of the rainbow are represented by emeralds, rubies, blue sapphires, tanzanites, yellow chrysoberyls, pink tourmalines, amethysts, blue topaz, orange spessartites and tsavorites.
The gemstones shimmer as a harmonious and expressive rainbow when the 10 watches in each set are placed side by side.
"We selected some of the world's purest and most vivid stones, and the challenge was to find 800 gemstones per watch, all with the exact same colour and the highest level of quality," said Nathalie Barzilay, Audemars Piguet's head gemmologist.
The sourcing of the perfect stones took approximately a year. After the supplier's rigorous selection, an additional check was carried out at Audemars Piguet to ensure homogeneity amongst the coloured gemstones selected per watch. Lastly, the purity and natural origin of each stone were then verified by an external laboratory.
With each gem being unique, the design, development, manufacturing and hand-setting were adjusted according to its typology, hardness and specific properties.
The rainbow project called for another collaboration with Salanitro, who worked on Audemars Piguet's first high-jewellery Diamond Trilogy in 2013 and Sapphire Orbe in 2019.
Based in Le Brassus since 1875, Audemars Piguet is the oldest fine watchmaking company still in the hands of its founding families. Founded in 1990, Salanitro is originally known for its gem setting but has now expanded its expertise to a full range of skills in crafting watches.
To match the architecture of the Royal Oak case, bracelet and dial, the gemstones were individually cut into baguettes of 179 different sizes for the 41mm watches and 153 sizes for the 37mm versions, before being polished by hand to achieve sharp and clear angles.
The quality of the cut is as important as the inherent quality and clarity. The custom-cut baguettes not only need to be eye clean (no visible inclusion by the naked eye), their lines and stepped facets have to be perfectly symmetrical and aligned to let the light shine through and emphasise the stone's purity and transparency.
The closed setting technique was used on the bezel, studs and crown, whereas on the dial and bracelet links, the beauty of the stones is enhanced by an invisible gem setting.
Tiny grooves were delicately incised in the baguette-cut stones, which were then carefully snapped one by one into a hidden rail mounted in the gold component, giving the impression that they are holding on their own. The complexity also included reaching flawless alignment between the different stones once set.
Audemars Piguet and Salanitro worked hand in hand through all stages of production, while retaining the aesthetic codes and ensuring water resistance, reliability, robustness and repairability.
The 37mm and 41mm white gold references are respectively equipped with calibres 5909 and 4309 featuring the "50-years" oscillating weight crafted in rhodium-toned pink gold.
Building on Audemars Piguet's legacy of high-jewellery watches, the two sets of Royal Oak Selfwinding collectively reinterpret the rainbow. Yet each timepiece also tells its own story of the dedicated precious stone.
