Rhodium plating
A thin electroplated layer of rhodium that gives white gold and silver a bright, cool white finish.
Why white gold is plated
Most white gold alloys are not perfectly white. Depending on the mix, they have a faint yellow or grey tint. Rhodium plating hides that tint and adds the mirror-like brightness customers expect from white metal.
How long it lasts
The plating is thin, so it wears on high-contact areas such as the underside of a ring shank. Many owners have rings replated every year or two, depending on wear. Sterling silver pieces are also plated to slow tarnishing.
Rendering plated white metal
In a render, rhodium plated white gold looks cool and very reflective, with almost no colour in its highlights. Unplated white gold looks slightly warmer, and platinum looks a little greyer and deeper. If you sell white gold that ships with rhodium plating, choose a bright, neutral white metal material so the image matches what the customer receives.
Keep roughness low for a polished finish. Because the surface is so reflective, the environment becomes the image. A studio environment with clean light panels produces crisp white reflections, while a dark environment makes white metal look like steel.
If you also offer yellow or rose gold, render the white version with the same camera and environment so the colour difference between variants is honest.