Meltio Helps Grow Rubies Inside 3D Printed Platinum

At the University of the West of England, a jeweler turned researcher is using metal 3D printing to grow gemstones directly inside precious metal settings. The result is a world-first approach to jewelry making that turns the casting process inside out.

Dr. Sofie Boons, Associate Professor of Craft and Design at UWE Bristol, leads the Neo-Gemstones project. Her team uses a Meltio Engine integrated with a HAAS 5-axis CNC machine to print structures from platinum wire. Because the build stays accessible during printing, the researchers can pause at any point, drop a tiny crystal seed into the structure, and resume depositing metal around it.

After the print is finished, the piece goes into a furnace with a flux solution. Over several days at high temperatures, new crystal material grows onto the seed, forming a ruby or sapphire directly inside the platinum setting. The team calls reuse of discarded gem material as seeds "urban mining."

Why This Matters Beyond Jewelry

Traditional casting makes it hard to position a delicate seed inside a metal form without shifting or contamination. Powder bed fusion keeps the part buried in powder, which is no better for precision placement. Wire-laser deposition keeps the build open, giving the operator exact control over where the seed sits.

The same approach could eventually embed sensors, markers, or inserts inside metal parts for aerospace, medical, or industrial applications. It shows that additive manufacturing can open a part during production instead of leaving the interior inaccessible until the build finishes.

A First in 2024

The Neo-Gemstones team produced the first ruby grown inside a platinum ring in 2024. The current work refines the process so jewelers can reliably produce pieces with gemstones grown in place rather than set after mining and cutting.