The Rayy’s Revolutionary “Light-Shaping” Lab-Grown Diamond Jewelry


About a decade ago, Romain Testuz, a student at the Swiss Federal Institute of Technology in Lausanne, grew fascinated by “the possibility of controlling light,” he says.

Under the guidance of a professor, he began to experiment with algorithms that could alter the way light is reflected on a surface. What started out as a theoretical effort became practical in 2016, when Testuz cofounded Rayform, a technology company that works with luxury makers to “sculpt light” on nearby surfaces, often as an anti-counterfeiting solution.

In September 2019, Testuz and his business partner, Yuliy Schwartzburg, parlayed the technology into a jewelry company called The Rayy, which makes a range of minimalist, unisex rings and pendants that can be customized to reflect sunlight into a personal message. The technology is based on an optical phenomenon known as caustics: “the effect you see when there’s sun at the bottom of the sea or a swimming pool, those beautiful abstract patterns of light when light passes through a wavy source of water,” Testuz says. “That’s the source of this project—concentrations of light that come through curved surfaces.”

By changing the curvature of a gold ring or pendant slightly, The Rayy can focus sunlight into a desired image. “Everything in jewelry is about light and how light interacts with matter, so this is just an extension of the possibilities jewelry designers can use,” Testuz says.

The Rayy Bar Snow rings star cosmic
The Rayy’s Bar Snow rings reflect custom messages in light.

Given the lab origins of his jewelry, it should come as no surprise that Testuz opted to feature lab-grown diamonds in the 18k gold collection.

“As we are originally scientists, we knew it was possible to create diamonds by replicating their natural growth conditions and we investigated in this direction,” Testuz tells JCK. “We soon discovered we could access lab-grown diamonds and we knew their origin, that they had been sustainably produced with renewable energy, and had no link to conflicts. Of course, they have the exact same physical properties as mined diamonds, which make them shine just as bright.”

The Rayy Dot Snow Leila ring
The Rayy’s Dot Snow Leila ring

The direct-to-consumer brand, designed by creative director Noémie Arrigo, allows clients to customize their gold jewels online and instantly preview the results. The Rayy’s most popular collection is called Bar—the pieces accommodate up to eight light characters. Testuz says most people opt for messages that capture personal details, such as wedding dates, initials, or special words.

The Rayy Dot Crown ring heart
The Rayy’s Dot Crown ring reflects a heart symbol made of light.

“Some people even send us small drawings or illustrations,” he says. “A pianist wanted the first notes of a piece she composed. And we can also work with non-Latin characters, such as Chinese, Arabic, or Russian. Once we know the message, we use a very precise computer-controlled diamond tool to sculpt the surface of the ring and form the desired surface waves. Thanks to the properties of the gold, daily wear like scratches will not affect the message appearance, and it can even be repolished.”

Top: Bar Snow ring in 18k yellow gold with lab-grown diamonds, $4,950; and Solitaire Snow ring in 18k white gold with lab-grown diamonds, $9,240

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By: Victoria Gomelsky

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