When it comes to making a statement, Richard Mille sure is an expert. From the rock-and-roll inspired RM 66 Flying Tourbillon to the diamond-set RM 07-01 Automatic Winding Intergalactic worn by Michelle Yeoh at the 2025 Golden Globes, the maison has become synonymous with bold timepieces that stand out from the crowd.
Richard Mille’s most recent launch — an extension of its RM 07-02 Automatic Sapphire collection — continues that design ethos. Among the four sapphire-clad watches that have been unveiled is a version in lilac, a brand-new colourway for the line.
While sapphire is most commonly known as a material used for watch crystals and clear casebacks, its use in other components has become increasingly popular over the past decade. Its high transparency, scratch resistance and hardness ensure durability while allowing for a clear view of the piece’s inner workings.
A colourful situation
The RM 07-02 Automatic Sapphire collection debuted in 2015 with a watch entirely encased in pink sapphire. Though the maison had launched sapphire cases three years earlier — with the RM 056 Tourbillon Split-Seconds Chronograph Sapphire — the RM 07-02 Automatic Sapphire marked its first time using coloured sapphire in this way.
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Making a sapphire case is no walk in the park, however. The sapphire itself requires incredible precision to grow. Richard Mille worked with Swiss firm Stettler to synthesise sapphires using the Kyropoulos method. Aluminium oxide is heated to between 2,000°C and 2,050°C in a controlled atmosphere before the crystal is allowed to grow from a seed over up to several weeks.
Many variables can affect the growth of sapphire. Uneven fluctuations in temperature, for instance, can cause irregularities in the crystal structure, which may then lead to stress points or even fractures and cracks.
Creating coloured sapphire — which involves introducing dopants to the mix — adds another layer of complexity to the process. At Richard Mille, multiple rounds of testing are conducted to get the right hues, especially when developing new colours, such as the new lilac RM 07-02 Automatic Sapphire.
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The incorporation of metal oxides into the crystal structure makes the sapphire much more sensitive to changes in temperature and growth rate. Strict controls are therefore needed to ensure that the final sapphires that go into Richard Mille’s cases are of the right quality, clarity and colour.
The work doesn’t get any easier even after the sapphires have been synthesised. The material is incredibly hard, making it difficult to shape and polish.
To achieve the tonneau shape that has become a hallmark of Richard Mille’s timepieces in sapphire, the maison had to develop new processes, working with tolerances of just a few micrometres. Over 1,000 hours of machining is needed for each sapphire Richard Mille case; this includes some 430 hours to pre-form the individual parts, and another 350 hours on polishing.
The new watches
Just seven pieces of each of the new RM 07-02 Automatic Sapphire models — two green, one pink and one lilac — have been created.
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The watches’ dials feature a geometric pattern that combines layers of texture and colour, further showcasing the precision and technical craft required to produce each piece. All four of the new RM 07-02 Automatic Sapphire models have gem-set dials, with diamonds, sapphires, orange spessartite, opals and other precious stones meticulously arranged in symmetrical configurations.
For maximal visibility, an anti-reflective coating is applied to the front and rear bezels. Depending on the colourway, each watch is paired with a navy blue, white or grey strap.
Powering the RM 07-02 Automatic Sapphire is the CRMA5 movement. Skeletonised to showcase further the watch’s inner workings, the calibre’s baseplates and bridges are rendered in red or white gold, depending on the model; the metal is microblasted and chamfered by hand.
The CRMA5 runs at a frequency of 4 Hertz, and has a power reserve of about 50 hours. The in-house automatic movement features a variable-geometry rotor, so the winding mechanism can be personalised to suit the wearer. The rotor is set with diamonds, catching the light when viewed from the sapphire caseback.
The gears of the going train, which transmits power to the movement, have teeth with a higher pressure angle of 20 degrees and a special profile. This increases the durability of the gears and raises the movement’s accuracy.
A free-sprung balance — which eliminates the regulator index — with variable inertia further improves the RM 07-02 Automatic Sapphire’s reliability. Four small, adjustable weights on the balance allow for more accurate and repeatable calibration.
Of the four additions to the RM 07-02 Automatic Sapphire collection, two — one in pink, and the other in green — have cases set with diamonds. While gem-setting might be a well-established craft when it comes to gold and other metals, it’s a whole other ball game with sapphire.
Lasers are used to drill the seats in which the diamonds will be placed; the room for error is minuscule, with the machines operating to levels of precision that can barely be seen with the naked eye, if at all. The hand-polished gold prongs are then crafted separately and inserted to form a row of settings.
With years of experience innovating with the boundless potential of sapphire in watchmaking, it’s no wonder that Richard Mille has mastered its craft, getting things perfect to the micrometre — literally. And though a decade has passed since the first RM 07-02 Automatic Sapphire first came into being, this latest extension to the collection proves that the maison isn’t done pushing boundaries just yet.
