Gold Plating
A thin layer of gold deposited over a base metal. Gives the colour of gold at a fraction of the cost, and wears off over time.
Plating thickness is measured in microns. Flash plating under 0.5 microns wears away within months of regular contact; heavy plating at 2.5 microns and above lasts years.
Gold filled and vermeil are different and better, because both carry far more gold and bond it more securely.
The trade terms are used loosely in India, where gold polish often means a very thin flash plating over brass or Korean metal.
What you will hear
“Gold plated and gold filled are the same thing.”
In fact: Gold filled carries roughly a hundred times more gold than standard plating and lasts correspondingly longer. The words are not interchangeable.
When you are buying
Ask for the micron thickness, not just the word plated. It is the only number that predicts how long the finish will last, and a seller who knows it is a seller worth buying from.
Micron Plating
The thickness of a plated layer, in thousandths of a millimetre. The single number that determines how long a finish lasts.
Gold Filled
A thick layer of gold mechanically bonded to a base metal, legally at least 5% of the item's weight. Far more durable than plating.
Gold Vermeil
Gold plating over sterling silver rather than base metal, at a defined minimum thickness. The best of the plated family.
Rhodium Plating
A thin layer of rhodium over silver or white gold, giving a bright white finish that resists tarnish.
Brass
A copper and zinc alloy with a warm gold tone. Strong and inexpensive, but it tarnishes and can react with skin.