The Rolex Lady-Datejust 28 in 18ct yellow gold, featuring a full diamond-paved dial and a diamond-set bezel, represents the absolute pinnacle of feminine horological jewelry. This specific configuration, often designated by the reference 279138RBR, is not merely a timepiece but a statement of ultimate luxury and craft. While the Datejust lineage has long been the backbone of the Rolex catalog, the 'paved' variants occupy a rare space where high-jewelry gem-setting meets robust mechanical engineering. This model is characterized by its brilliant-cut diamonds that saturate the dial, contrasted by elegant black Roman numeral markers that ensure legibility is not sacrificed for shimmer. Collectors and high-net-worth individuals gravitate toward this model because it embodies the 'Presidential' aesthetic in a more delicate 28mm diameter, offering a seamless blend of the brand's most prestigious materials. It exists to serve a clientele that demands the reliability of a Rolex Oyster case with the uncompromising opulence of a diamond-set masterpiece. In the contemporary market, such factory-set pieces are highly coveted, as they represent a level of quality control and stone-matching that aftermarket modifications can never replicate. This model remains a perennial favorite in the primary market and a stable performer in the secondary market, symbolizing both personal achievement and enduring style.

The technical foundation of this Lady-Datejust is the 28mm Oyster case, milled from a solid block of 18ct yellow gold, cast in Rolex's own foundry to ensure metallurgical purity. At its heart beats the Calibre 2236, a self-winding mechanical movement entirely developed and manufactured by Rolex. This movement features the patented Syloxi hairspring in silicon, which provides exceptional resistance to magnetic fields and temperature variations, ensuring the watch maintains its Superlative Chronometer status (-2/+2 seconds per day). The architecture includes a screw-down Twinlock winding crown and a sapphire crystal with the iconic Cyclops lens over the date aperture at 3 o'clock. The bezel is meticulously set with large, brilliant-cut diamonds, precisely aligned to maximize light return. The dial is a work of art in itself, featuring a 'paved' technique where gold beads hold each diamond in place, creating a shimmering carpet of light. The watch is presented on the iconic President bracelet, characterized by its semi-circular three-piece links, which includes ceramic inserts inside the links to prevent 'stretch' and ensure longevity. With a water resistance of 100 meters (330 feet), the technical construction ensures that despite its delicate appearance, the watch possesses the same rugged durability inherent to all Rolex Oyster Perpetual timepieces.

The Lady-Datejust was first introduced in 1957, bringing the innovation and elegance of the original 1945 Datejust to a smaller, more feminine scale. Over the decades, it has evolved through several generations, with the 28mm 'modern' era beginning in 2015 to replace the previous 26mm standard. This transition marked a significant upgrade in both presence and technology, introducing the Calibre 2236 movement. Historically, the yellow gold and diamond-paved configurations have been the choice of world leaders, icons of cinema, and pioneers of industry, cementing the 'Lady President' as the gold standard for women's luxury watches. This specific iteration reflects the modern trend toward 'jewelry-first' horology, where the watch serves as a primary accessory. It fits into the Rolex timeline as a bridge between the functional tool watches of the mid-century and the high-jewelry masterpieces of the 21st century. By maintaining the classic Roman numeral indices amidst a sea of diamonds, Rolex pays homage to its traditional design language while pushing the boundaries of gem-setting. The 279138RBR is the culmination of over sixty years of refinement in the Lady-Datejust collection, representing the most technologically advanced and aesthetically refined version to date.