Researchers Grow Rubies Inside 3D-Printed Platinum Structures

At the University of the West of England Bristol, the Centre for Print Research is using metal 3D printing to grow gemstones inside platinum structures. The team integrates a Meltio Engine with a 5-axis HAAS CNC machine and deposits platinum wire to build open metal frameworks. They can pause the build, slip a tiny crystal seed inside, and resume printing around it. That seed later grows into a ruby or sapphire inside the finished part.

Why hybrid manufacturing fits the task

The challenge is placement. Molten metal flows around a seed during casting. Powder bed fusion buries the part in powder. Both make precise seed positioning difficult. Wire-laser deposition keeps the build accessible. The researchers stop at the desired depth, place the seed, and continue welding metal around it.

The same machine can switch to CNC machining to finish the part. Keeping everything on one build platform avoids repositioning errors. Dr. Sofie Boons, Associate Professor of Craft and Design at UWE Bristol, leads the Neo-Gemstones project. A jeweler turned researcher, she has spent several years developing lab-grown gemstones from waste material.

Urban mining and waste as a resource

Boons's method starts with discarded gemstone material, reused as seeds for new crystals. She calls it urban mining. In 2024, the team grew a ruby directly inside a platinum ring. The resulting crystal has the same structure as a mined ruby. The difference is the source and the location.

After the metal structure is complete, it goes into a furnace with a flux solution containing the material needed to form more ruby. Over several days at high temperatures, new crystal material grows onto the seed. The process turns a finished metal component into both vessel and growth chamber.

Beyond jewelry

The ability to pause a metal build, insert something inside, and continue printing could eventually help embed sensors, markers, or inserts inside metal parts. Additive manufacturing can open a metal part during production rather than leaving the interior inaccessible until the build is finished.

Meltio's wire-laser technology makes the approach practical. The UWE team uses platinum wire specifically for the research, but the same workflow could apply to other materials and other insertion tasks. The project is part of a broader push to make additive manufacturing more modular and embeddable.

The bigger picture

Gemstone growth inside metal is a small story with a large implication. If researchers can reliably place and grow objects inside printed metal, the technique could extend to medical devices, aerospace components, and industrial tools. The UWE team is not just making fancy rings. They are testing a new kind of hybrid manufacturing that treats a 3D-printed part as a living scaffold.