Solid, Filled, Vermeil or Plated: Reading Jewelry Marks
- Trinket File
- Metals and Stones
- 17 Feb, 2026
A stamp on jewelry is a declaration, not a guarantee. It’s still the most useful information you have, and the difference between a piece that survives daily wear and one that looks tired in a year is usually written in it.
What a hallmark is
A hallmark is struck or laser-applied by an assay office, which tests the metal before marking it. In the UK, pieces above set weights must be hallmarked before they can be sold as gold, silver, platinum or palladium: over 1 g for gold and palladium, 7.78 g for silver and 0.5 g for platinum, per the Assay Office London dealer’s notice. Other countries have their own systems, and some rely on the maker’s stamp alone. The US is one of those: there’s no mandatory assay, and marks are governed by the FTC’s Jewelry Guides and the maker’s own responsibility.
A full UK hallmark usually has:
- A sponsor’s or maker’s mark, identifying who submitted it.
- An assay office mark, showing where it was tested.
- A fineness mark, the proportion of precious metal.
- A date letter, the year it was marked (optional on modern pieces).
You’ll often see a fineness number with none of the rest. It may be a legitimate maker’s stamp on a piece under the hallmarking weight, or a manufacturer’s stamp with no independent testing behind it. To a buyer they look identical.
Fineness numbers
Fineness is parts per thousand. The ones to recognize:
| Metal | Marks |
|---|---|
| Gold | 375 (9K), 585 or 583 (14K), 750 (18K), 916 or 917 (22K), 999 (24K) |
| Silver | 925 (sterling), 958 (Britannia), 800 (often older continental) |
| Platinum | 950 most common; 900 and 850 also used |
| Palladium | 950 and 500 |
Two things follow. Higher fineness means softer metal: 22K scratches and dents more easily than 9K, and 24K is close to unusable for a daily ring. And an alloy is a mixture, so the rest is other metals (copper, silver, zinc, palladium, nickel) chosen for color, hardness and workability. That’s why two 18K pieces can behave differently and why some people react to one white gold and not another.
Plated, filled, rolled and vermeil
Most affordable jewelry is base metal with a precious layer, and the labels aren’t interchangeable. US definitions below are from the FTC Jewelry Guides (16 CFR Part 23).
Gold plated or gold washed means a thin gold layer over base metal, commonly brass, copper or steel. It’s measured in microns, and the thickness is rarely stated on the piece. The FTC no longer treats “flashed” or “washed” as safe terms for plating thinner than 0.175 microns of fine gold, which tells you how thin these can get. Expect wear at the contact points: the back and edges of a ring, the tip of a clasp, the outer curve of a bracelet.
Gold filled (historically rolled gold) is a much thicker layer of at least 10K gold mechanically bonded to base metal. In the US, “gold filled” means the gold layer is at least 1/20 of the total metal weight, so “1/20 12K” means one-twentieth of the weight is 12K gold. Below that, the term is “rolled gold plate,” with the fraction disclosed, such as “1/40 12K RGP.” Because the layer is so much thicker than plating, gold filled pieces wear far longer before base metal shows.
Vermeil is sterling silver with a gold layer. US rules set it at 10K or finer gold at least 2.5 microns thick throughout. Definitions vary by country, so outside the US treat the word as a description of construction, not a guarantee.
Rhodium plating is a thin, hard, white metal layer over white gold or other metals for a bright finish. It wears, and white gold rings are commonly re-plated when the warmer color underneath starts to show.
What the mark doesn’t tell you
- Plating thickness. “Gold plated” can mean a flash coat or a durable layer.
- Whether the stamp is genuine. Counterfeit and mis-stamped pieces exist, and stamps can be put on base metal.
- What a stone is. Marks cover metal only.
- Age and provenance. A date letter helps date a hallmarked piece; a bare number proves nothing about history.
- How it was made. Cast, die-struck and hand-fabricated pieces can carry identical marks and behave very differently.
- Hollowness. US rules say hollow gold should be disclosed (“14K Gold-Hollow Center”) and never called “solid,” but the stamp itself won’t show it.
Inspect a mark without damaging anything
Use a loupe or phone macro in daylight, surface clean of hand cream. Check the mark sits on the metal, not on top of a plating edge, and that the number is a recognized one. On a chain, check the tag by the clasp as well as the chain.
Look at high-wear spots at the same time: inside a ring shank, the back of a pendant, bracelet edges, prong tips. Wear-through shows as a color change, a yellower or grayer patch at an edge or a faint halo where plating has thinned. That tells you more about remaining life than any stamp.
Skip two tests. Acid and scratch tests permanently mark a piece, and home kits are too unreliable to settle a dispute. Magnet folklore is mostly wrong: a magnet can flag strongly magnetic base metal, but one not sticking tells you almost nothing, because most precious alloys aren’t magnetic. For certainty, ask a jeweler for an X-ray fluorescence test, which is non-destructive, or send it to an assay office.
Match the mark to the job
Metal and construction decide how much care a piece needs. A gold filled chain worn daily can be expected to outlast a flash-plated one by a wide margin. A rhodium-plated ring will need re-plating eventually. A 22K bangle shows fine scratches fast, and polishing it repeatedly removes metal for good.
Two rules. Structural advice from a jeweler is usually worth more than a stamp: a workshop can see how thick the metal is, where joints were made and whether a clasp suits the weight. And if composition matters to you (an allergy, an heirloom, or a price that assumes solid gold), get it in writing before you buy, and treat unwritten promises as unproven.
