Vault Unlocked: Inside Piaget’s world of rare gemstones with Guillaume Chautru
Guillaume Chautru, the man in charge of gemstones at Piaget, has a background as vivid as the stones he hunts. Formerly a zoologist with a very specific focus, Chautru’s fascination with colour led him into the study of gemstones. Now, as Piaget’s head of gemmology, he combines scientific expertise with an adventurer’s spirit to source and shape extraordinary stones that define the maison’s bold and colourful identity.
Tatler caught up with him over a video call to explore his journey from exotic terrains to exquisite creations.
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Guillaume Chautru finding the right diamonds to gem-set the Piaget Aura dial
How did you get into gemmology?
It’s a funny story. Before being a gemmologist, I was a herpetologist [an expert in amphibians and reptiles]. The common point between [my two] passions is colour. When I was a herpetologist, I was running after the most colourful snakes in the world, and with stones, it’s the same. I’m running after the most colourful stones in the world from country to country. So basically, it came full circle.
Can you share one of your most memorable experiences of sourcing a gemstone?
One of the most interesting stories is about a masterpiece we call the Piaget Blue; I bought it about ten years ago. Our previous CEO asked me to find an incredible stone—a blue sapphire over 50 carats. In the past, customers accepted inclusions because such items are very scarce, but today, customers want top stones, top cuts and no inclusions. So, a 50-carat blue sapphire with top colour is a big deal. I heard about an incredible Burmese sapphire, a 50-carat square cushion, which is the most in-demand shape for a sapphire and the most difficult to get; I had never seen one in my life. The stone disappeared from the market, and I spent almost a year and a half searching for it. It was in a private collection, but I didn’t know where.
By chance, I was at the Hong Kong Jockey Club with a friend, and when I told him about the stone, he said, “That’s my uncle’s stone.” His uncle is one of the biggest collectors in the world, but I didn’t know at that time. It took almost another year to convince his uncle to sell it to Piaget—not because of the money, but because we respect and understand what the stone is [and so, how much he valued it]. It was one of the funniest and most difficult items I have ever found, but I am still searching for stones even now—so maybe next interview, I’ll have a new story.
What are the challenges of working with natural stone dials on Piaget watches?
From a gemmological point of view, everything we do in watchmaking is extremely difficult. The dials are very thin—about 0.4mm. Big pieces, like the Andy Warhol Watch, which has one of the biggest dials, require the highest quality [of stone]. Sometimes I tell marketing, “If you want me to [find higher quality stones], send me to another planet because these [are all] we have on Earth.” Sometimes when we offer customers raw stone dials and make them choose three, because during the process, two [are sure to] break. Sometimes we even break ten. It’s very technical.
Also, duplicating a dial is difficult because natural material varies, and we must ensure all watches worldwide have the same colour and quality. For example, for the Aura Rainbow collection, it took me eight months to select and cut the rough stones and four more months to adjust them one by one. The colours must match perfectly. For me, making the Aura Rainbow [pieces] is much harder than finding centre stones for high jewellery.
The Piaget Aura Rainbow watch
Could you share a story about a Piaget creation that is particularly close to your heart?
The [Piaget] Aura [high jewellery watch] we did last year with shades of pink sapphire and ruby is very dear to me. People often ask me about my favourite stone; I don’t have one, but pink sapphire speaks to me, including padparadscha. These stones are very strong in colour, tough and have great lustre.
For the Aura watch, I created a gradation of pink like a rainbow, with four rubies in the middle and different shades of pink sapphire. Matching all those colours was a challenge, especially since pink sapphire is hard to find. I was [still] missing five stones when the company closed for Christmas. I spent my holiday searching for them … to ensure the full batch was ready for Watches and Wonders in March.
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What impact does technology have on gem-setting?
Gem-setting today still relies heavily on human skill; there isn’t a machine yet that can achieve what a skilled artisan can do by hand. However, technology is helping us push boundaries. All our high jewellery stones—whether for watches or jewellery—are now 3D-scanned. We use these scans to print models or recut stones, allowing the setter to practise and prepare using replicas rather than the real precious stones, which could be damaged or lost during the process. This is especially important for centre stones or exceptional gems. When we 3D scan a stone, we create a unique digital fingerprint for it.
In fact, about ten years ago, we were among the first to implement traceability processes in manufacturing. If you brought a Piaget stone back to us even 20 years from now, I could tell you with absolute certainty if it’s an original Piaget stone, if it’s been recut or treated, or if anything else has happened to it. Technology allows us to do incredible things, but at the end of the day, you still need the human touch and the craftsmanship of our artists at Piaget.
What stone do you think will become popular in the future, and why?
[Even though] it’s already scarce: Pietersite. We’ve started working with it, although it’s not an easy stone to handle. What makes Pietersite interesting is its blue-grey colour; any blue stone tends to do well because people love blue tones. Pietersite also has an optical effect, somewhat similar to tiger’s eye or falcon’s eye, but with a mother-of- pearl sheen and blue highlights. Each stone has a different pattern, so every piece is unique.
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