Rolex Datejust 31 Yellow Rolesor — Domed Diamond Bezel Mother-of-Pearl Diamond Dial | Ref. 278343

Reference 278343 represents the Datejust 31 at its most decorative — a Yellow Rolesor configuration featuring a domed diamond-set bezel alongside a mother-of-pearl dial further enriched with diamond hour markers. Yellow Rolesor combines the robustness of Oystersteel for the case and bracelet with the warmth of 18ct yellow gold on the bezel and crown, a combination Rolex has refined over decades of Rolesor production. The domed diamond bezel, rather than the more common fluted style, creates a softer, more jewellery-forward silhouette.

Driving this reference is Calibre 2236, introduced in 2015 as the successor to the long-serving 2235. The 2236 marked a generational leap for Rolex's mid-size movements: its Syloxi silicon hairspring — manufactured in-house at the Rolex facility in Plan-les-Ouates — achieves isochronism performance previously unattainable with metallic hairsprings, while its antimagnetic properties and precision make it future-proof against the increasingly magnetic environments of modern daily life. A power reserve of approximately 55 hours, improved from the 2235's 48 hours, adds practical convenience.

The 278343 occupies a sweet spot in the current Datejust 31 range — decorative enough to function as a jewellery piece, yet mechanically substantial as a Superlative Chronometer-certified instrument. The combination of yellow Rolesor, domed diamond bezel, and mother-of-pearl with diamonds produces a watch with considerable visual depth, its layered reflectivity responding to changing light throughout the day. For collectors building a comprehensive Datejust study, this reference exemplifies how Rolex deploys gem-setting across different bezel profiles and dial materials to create distinct personalities within a unified design language.