TEYING BUYER GUIDE · UPDATED OCTOBER 1, 2026

How to Verify Gold Plating Thickness: XRF Tests and Micron Tiers

Plating thickness is a number a supplier states and a lab can measure. This explains the 0.5, 1, 2.5, and 3 micron tiers, how XRF testing reads a coating, how many points to measure and where, what a plating report has to show, and what the FTC definition of vermeil actually requires.

By Qiu Qiu, Founder and Design Lead at TEYING · October 1, 2026

The short answer: ask for a number, then measure it

A plating claim is only as good as the number behind it. Ask the factory which layer the micron figure describes, ask for the thickness as a range, then have an XRF test confirm it on a production piece. XRF reads a coating without damaging the piece, and a report that names the measurement positions, the layer model, and the uncertainty is what turns a claim into evidence.

The micron tiers you will see, and what each one is for

Thickness is not the only variable. A ring worn daily meets a palm, a desk, and water, while a pendant touches fabric occasionally, so the same coating behaves differently on each.

TEYING quotations sit in the 0.5 to 2.5 micron range for the gold color layer, chosen per SKU, produced with a four-layer premium electroplating process with nano vacuum coating. If a design calls for 3 microns or more, put it in the brief before quoting, because it changes plating time and cost.

How XRF measures a coating

XRF stands for X-ray fluorescence. The instrument directs X-rays at the piece, the atoms in the material respond with energies characteristic of each element, and the detector reads which elements are present and in what proportion. With a coating model loaded for the material stack, the instrument converts that signal into thickness, reported in microns.

Four properties are worth knowing before you rely on a reading.

• It is non-destructive. The piece is not cut, dissolved, or marked, so the tested unit can go back into the shipment.
• It measures a spot. The beam covers a small area, and the reported thickness is an average over that spot under the chosen model, not the whole piece.
• It reads composition as well as thickness, flagging elements in the base alloy or an intermediate layer before a lead, cadmium, or nickel question becomes a shipment problem.
• It depends on the model. Gold over copper over brass with a top coat reads differently from gold directly on brass. If the layer stack entered into the instrument does not match the piece, the number can be wrong while the instrument is working perfectly.

For a disputed figure, an accredited lab can run a reference method such as a gravimetric or acid-based determination.

Where to measure, and how many points

A single reading on one flat surface will flatter any coating. Spread the measurements and record where each one was taken.

• Take eight to ten readings per SKU across different areas of the piece.
• Cover both faces: the outer surface the customer sees and the inner band or back where wear actually happens.
• Include an edge, a recess, a prong or setting, and the inside of a curve. These are the areas plating reaches least evenly.
• Record the position of each reading, so the sample report and the production report can be compared point by point.
• Test a sample-approved piece and a random piece from the bulk run. If the two disagree, the question is the plating bath, not the instrument.

Flat surfaces give the cleanest readings. Treat readings from curved, filigree, and recessed areas as secondary: they normally run lower, which is geometry rather than a defect, and it is where the customer first notices wear.

What a plating report should show

Ask for these seven items. A report missing any of them is a claim rather than a measurement.

1. Instrument make and model.

2. Calibration standards used, with dates.

3. Number of measurements and their positions on the piece.

4. The layer model applied, and which layer the micron figure describes.

5. The result as minimum, average, and maximum, in microns, with the unit stated.

6. Measurement uncertainty and the test date.

7. The SKU and the batch the tested piece came from.

The recurring trap is a report that says "2.5 microns" and nothing else. Which layer, which positions, average or maximum, which batch. Until those are answered, the number is not usable, whatever the supplier relationship.

Vermeil: what the word is allowed to mean

The FTC Guides for the Jewelry, Precious Metals, and Pewter Industries define the term at 16 CFR 23.5, and three conditions apply together.

• The base must be sterling silver, 92.5% silver.
• The gold or gold alloy coating must be at least 10 karat.
• The coating must be at least 2.5 microns thick on all significant surfaces.

Two of the three is not vermeil. A brass piece with 2.5 microns of gold is heavy plating, and describing it as vermeil misstates the product. A 925 silver piece with a 1 micron gold layer is gold-plated silver, and the thickness is what fails. The guides are reviewed periodically, and the fineness safe harbor has been the subject of comment in past reviews, so confirm the current text before printing packaging.

The definition also varies by market. General guidance only, not legal advice. TEYING treats vermeil as a gold layer over 925 sterling silver, with the exact definition confirmed for the buyer's market. If you plan to use the word on a label, get the plating record and the thickness measurement first.

Writing the plating requirement

A plating brief a factory can quote and a lab can verify has four lines: base material per SKU, gold color and finish, target thickness as a range with the layer named, and the wear expectation. Add one more line if you intend to test: say so before production, so the plating route and the sampling plan are set up for it.

If you are developing a plated collection and need the thickness documented, send the reference image and the wear expectation through the TEYING quote form. We will confirm base material, finish, and the plating tier for the price point, and discuss which test documentation can be provided for your market.

FAQ

How do I verify gold plating thickness on jewelry?

Ask which layer the quoted micron figure describes, then have the piece measured by XRF at an accredited lab. Take eight to ten readings across flat and high-wear areas, and compare a production piece against the approved sample. The report should state the layer model, the positions measured, the result range, and the uncertainty.

Can I test plating thickness without damaging the jewelry?

Yes. XRF is non-destructive, so the tested piece can be returned to stock. Methods that require dissolving or cutting the sample are used only when a reference result is needed for a dispute. Ask the lab which method it will use before sending the pieces.

Is 2.5 microns the same as vermeil?

Only when the base is 925 sterling silver and the gold is at least 10 karat, which is the FTC definition at 16 CFR 23.5. A base metal piece with a 2.5 micron gold layer is heavy plating. Confirm the rule for the markets you sell into before using the word on a label or listing.

Does thicker plating stop jewelry from wearing or tarnishing?

No coating outlasts unlimited abrasion. A thicker gold layer means more material to wear through before the base shows, which stretches service life, not permanence. Tarnish is a surface reaction and is addressed by the protective top coat, the base material, and care, so consistent wiping and storage still matter.