Arnold & Son continues its exploration of rare and unprecedented materials in watchmaking. Charoite, a delicate mauve with fine white veins, brings its noble shade to the Double Tourbillon grand complication. Set off by the white gold case, skeletonised bridges and pure white opal subdials, charoite gives this one-off piece a unique elegance. In terms of pure watchmaking, Double Tourbillon draws on the Manufacture’s design, production, finishing and adjustment capabilities. Its sapphire crystal is convex to accommodate the depth of its two tourbillons, which are in turn each secured to a three-dimensional, skeletonised, cantilevered bridge in white gold. The A&S8513 calibre is thus equipped with two barrels, two crowns and two time zones.