UWE Bristol Is Growing Gemstones Inside 3D Printed Platinum Structures

At the University of the West of England Bristol, the Centre for Print Research is doing something that sounds like science fiction: growing gemstones directly inside metal structures 3D printed in platinum. The project, called Neo-Gemstones, combines wire-laser directed energy deposition, five-axis CNC machining, and crystal growth in a workflow that has already produced a ruby set inside a platinum ring.

The team, led by Dr. Sofie Boons, Associate Professor of Craft and Design, uses a Meltio Engine integrated into a HAAS CNC machine. The system deposits platinum wire layer by layer, building up complex geometries that would be difficult to achieve through casting or traditional machining. Because the build remains accessible during printing, the researchers can pause the process, place a tiny crystal seed inside the partially finished structure, and then continue depositing metal around it.

Why pause the print

Casting makes it nearly impossible to position a seed inside a closed mold without damaging it. Powder bed fusion buries the part, so the seed would be lost in the powder. Wire-laser deposition keeps the build open. That single detail changes what becomes possible. The seed can be positioned with precision, and the metal structure can be built to hold it exactly where needed.

After the metal structure is complete, it goes into a furnace with a flux solution. Over several days at high temperature, crystal material grows onto the seed, forming a ruby or sapphire inside the platinum. Because the seed comes from recycled gemstone waste, the team calls the approach urban mining. The resulting gem has the same crystal structure as a mined stone, but it is grown in a shape and location chosen by the designer.

Material efficiency and recovery

Platinum is expensive, and waste is costly. CFPR researcher Michael White developed an extraction system that captures platinum removed during CNC machining. Instead of becoming scrap, the material is collected at source and reprocessed. That recovery system matters for a project where every gram of precious metal is accounted for.

The researchers are also testing other materials. Stainless steel is cheaper and easier to work with for prototyping complex forms. Platinum-palladium alloys may work better with the furnace process used for crystal growth. The team is evaluating which combinations give the best chemical resistance and thermal stability for different applications.

Beyond jewelry

The immediate output is jewelry, but the underlying capability has broader implications. Being able to pause a metal build, insert an object, and resume printing could eventually be used to embed sensors, electronics, or other inserts inside metal parts. Additive manufacturing typically leaves the interior of a part inaccessible until the build finishes. This approach opens the part during production, which is a different way of thinking about how metal parts can be made.

The Neo-Gemstones project is still a research effort, not a commercial line. It does show how hybrid manufacturing can move beyond making existing parts faster. Here, the technology is exploring what becomes possible when deposition, machining, and manual intervention all happen in the same workflow. A platinum structure becomes the environment for a gemstone to grow. That is a genuinely new use of metal 3D printing.