Rolex’s history with “rainbow” gem-setting dates back to the late 1970s, when it began adorning the bezels of its Cellini models with multi-coloured sapphires in a gradient, at times extending this vibrant display throughout the bracelet. However, the modern hype around rainbow gem-set watches truly began with the 2018 release of the Everose Rainbow Daytona (ref. 116595RBOW). As with many of the more peculiar Rolex watches, it has become something of a cult object and is an excellent example of the brand’s in-house technical expertise in gem-setting. Its debut came a few years after Rolex had quietly discontinued the earlier Rainbow Daytona models in yellow gold (ref. 116598RBOW) and white gold (ref. 116599RBOW), both originally launched in 2012. However, nearly two decades before the 2012 release, Rolex had already produced a one-of-a-kind Cosmograph Daytona ref. 16599SAAEC in white gold with a bezel embellished with rainbow-coloured sapphires around 1994 for a Middle Eastern client.

This unique commission arrived six years after the birth of the first automatic Daytona, ref. 16520 in 1988. As with the appeal of gem-set watches in general, the higher the stakes in technical accomplishment within the movement, the more captivating the result. Equipped with the legendary El Primero movement which was further modified by Rolex to meet their own rigorous standards, the automatic Daytona became a fitting canvas to showcase the high craft of gem-setting. Rolex first began offering the option of diamond hour markers but between 1994 and 1999, the manufacture went full throttle with a variety gem-set bezels, ranging from sapphires to emeralds and rubies. However, these were single-coloured stones often paired with diamonds. The unique Rainbow Daytona ref. 16599SAAEC was hence perhaps the most unusual and audacious variation on their classic racing chronograph.

Its SAAEC designation at the end of the reference number stands for “Sapphire Arc-en-Ciel,” which means “Sapphire Rainbow” in French. Although Rolex had produced Rainbow Day-Date models since the 80s, the Daytona was clearly a very different specimen, squarely regarded as a sports watch designed for professional racers and athletes, hence embellishing it with a bevy of colourful sapphires was quite an extraordinary step for the brand.

Rainbow Daytona References

The Rainbow Daytona was officially introduced in the catalog only in 2012 in 18k white (ref. 116599RBOW) and yellow gold (ref. 116598RBOW) featuring a ring of 36 multi-coloured baguette-cut sapphires on the bezel. The stones have a very precise and gentle colour shift from piece to piece. Each stone is flanked by two others that are similar in hue but not identical, creating a gradient that flows from crimson red at 12 o’clock to radiant tangerine, lemon yellow, and forest green, to blue, purple, lilac and magenta, before cycling back to crimson once more. The top surface of the lugs and the crown guards were set with a total of 56 brilliant-cut diamonds.

Rolex has assembled a full team of gemologists and gem-setters who employ advanced technologies, including spectrometers and X-ray imaging, to analyse and match the stones. These tools assist in assessing various properties, such as colour, clarity, cut, and carat weight. Each sapphire must possess a precise hue, saturation, and transparency. Additionally, they need to have exact geometry so that each stone fits flush against the others. As such, many stones are discarded in the process. The gem-setter then meticulously sets each stone piece by piece. The need for both optical and geometric precision contributes to the high level of skill and effort required in gem-cutting and setting.

The dial is black lacquer while the sub-dials have a “gold crystal” pattern that resembles meteorite at first glance but was achieved through a crystallization process developed by the manufacture. These early models are distinguished by the Arabic numerals at the quarters along with brilliant-cut diamond hour markers, and hands coated in red varnish.

The white gold version was made of a new gray gold alloy which was granted a patent that same year. The alloy is free of nickel and copper, which are common allergens, while being sufficiently hard with a high whiteness and does not require rhodium plating.

In 2018, Rolex introduced the Rainbow Daytona in 18k Everose gold (ref. 116595RBOW). The proprietary alloy was developed to improve resistance to colour changes caused by mildly corrosive aqueous media such as saltwater over time while obtaining the perfect rosy hue. This was achieved using optimal amounts of palladium and indium, as well as silicon and calcium.

The ref. 116595RBOW came with either a black lacquer dial or a fully pavé diamond dial. Notably, in this new model, the diamond hour markers were replaced with rainbow-coloured baguette-cut sapphires to match the bezel. The sub-register hands were coated in black varnish while the chronograph seconds hand is in pink gold.

In 2022, white gold (ref. 116599RBOW) and yellow gold (ref. 116598RBOW) versions were quietly launched featuring the same updates. These 2018 and 2022 models are still in production. Naturally, all of these models were equipped with the in-house vertical clutch Calibre 4130 introduced in 2000.

The Rainbow Zenith ref. 16599SAAEC

While the Calibre 4130 is one of the most sophisticated and thoughtfully engineered vertical clutch movements in watchmaking – built not only for performance but also ease of service – the Zenith Daytona calibre 4030, which powers the ref. 16599SAAEC, has always held a special place due to the brand’s obsessive degree of modifications. Totalling in excess of 200, it ranged from having a more robust ratchet system in the reverser to the use of involute tooth profile on the fourth wheel for more stable torque transmission to having recesses on the teeth of the escape wheel to retain lubricants. The outstanding degree of modifications has made it a species of its own.

Like the El Primero calibre, the Calibre 4030 has a horizontal clutch. Horizontal clutch automatic winding chronographs are increasingly uncommon in watchmaking and are a reflection of a transitional period in chronograph development. However, while the hallmark of the El Primero Calibre 400 was its high frequency of 36,000 vph, allowing for elapsed time measurement down to a tenth of a second, Rolex lowered the frequency to 28,800 vph to enhance durability and power reserve, which could now be extended by approximately four hours. Most notably, the calibre 4030 did away with an adjustment index and was fitted with a free-sprung balance wheel with Microstella nuts. Furthermore, the balance was attached to a Breguet overcoil hairspring. These meticulous modifications were no doubt aimed at achieving Superlative Chronometer certification.

On the outside, the watch is visually very different from the later standard production models. While not obvious at first glance, the bezel features 44 baguette-cut sapphires instead of the usual 36. This results in a more delicate colour gradient that beautifully expands upon a chosen hue.

Notably, the colour spectrum is in a reversed order, and while the production version showcases vibrant scarlet red and azure at 12 and 6 o’clock, respectively, the ref. 16599SAAEC opts for pastel shades in these positions, lending it a more subdued appearance. However, the overall effect is anything but understated; it is complemented by a full diamond pavé dial adorned with blue brilliant-cut sapphire hour markers. The colour matching of the stones and the quality of setting are admirable achievements of a highly demanding craft and reflects Rolex’s renowned perfectionism.

At the cardinal points on the dial are Arabic numerals, which carried over into the 2012 models. The hands are all in white gold and the watch has a signed white gold folding clasp.

It’s the stuff legends are made of; not only was it a precursor to the Rainbow Daytona but also a unique commission and fresh to market. It has an estimate of over CHF 3 million and will be sold on November 8, 2024 at the Hotel President in Geneva as part of the Reloaded: The Rebirth of Mechanical Watchmaking, 1980-1999 sale.