A micron, or micrometre, is one-thousandth of a millimetre. Gold plating thickness is measured in microns, and a difference that sounds tiny, such as 0.2 against 1 micron, makes a large difference to how long the colour lasts.
The useful question is not only how many microns you need, but how you will write it into an order and check that you received it.
How much you need
As typical guides, flash plating is well under 0.5 micron, standard fashion plating sits around 0.5 to 1 micron, and heavy gold plate is often 1 to 2.5 microns. Pick the level for each product by how much rubbing it gets, as explained in our article on gold plating thickness.
Some markets attach meaning to these numbers. In the United States, the FTC's jewellery guides set minimums for terms such as gold electroplate and heavy gold electroplate, and gold vermeil means a sterling silver base with at least 2.5 microns of gold. Only use those terms if your pieces meet the definition.
How to write it into a purchase order
- Plating type and colour, such as yellow gold, matched to an approved sample.
- Minimum gold thickness in microns, measured on a named significant surface, such as the front face.
- The underlayer, such as nickel-free barrier, if you sell in Europe.
- Any lacquer or anti-tarnish coat.
- The test method and how many pieces will be measured per lot.
- What happens if a lot measures below the minimum: replating, replacement or a price adjustment.
How thickness is checked
- XRF (X-ray fluorescence): non-destructive and quick, the common method for plated jewellery at labs and larger workshops.
- Cross-section under a microscope: the piece is cut and measured directly, which is accurate but destroys the sample.
- Wear tests: abrasion or sweat tests show how the finish performs, which is a useful check alongside thickness.
Why measuring matters
Plating time and gold use are easy places to save money, and a thinner layer looks the same on the day it ships. Only measurement shows the difference. Test approved samples, then test pieces drawn at random from bulk, and keep the reports with each lot. See how to make sure bulk matches the approved sample.
What this means for a buyer
Write a number, a method and a remedy into every order. Creston & Co works for buyers only, for a fixed fee agreed in writing, draws samples from bulk at the Rajkot workshop and sends them to accredited labs for thickness testing before you pay the balance. Ask for a free sourcing review.