Machined or Cast: Why the Difference Matters

Two ways to make a shape

Every metal object begins as one of two processes. Machining removes material: a solid bar of certified metal is cut, turned and milled until the exact shape emerges — like carving from a single block. Casting adds material: metal is melted and poured into a mould, then cooled into the shape — like pouring jelly into a mould.

What casting can hide

• Porosity. As cast metal cools, tiny bubbles and gaps can remain trapped inside — invisible from outside, weaker in reality.
• Surface texture. Cast surfaces typically need heavy polishing to become smooth, and porosity can open up right at the surface.
• Material dilution. Casting often blends metals into alloys, blurring exactly what the finished piece contains.

What machining preserves

Because machined jewellery starts from solid certified bar, the material keeps its documented purity and density from the mill certificate to the finished piece — nothing was melted, blended or re-formed along the way. That is why professional piercing jewellery for healing piercings is machined as standard. Read about the certification chain in what implant-grade certification means, or return to the jewellery guide.