The quick answer
The most reliable sign is the mark stamped on the piece. Gold filled jewellery is usually marked GF, G.F. or with a fraction and karat such as 1/20 12K GF. If you can find a mark like that, you almost certainly have gold filled. The other checks below help when the mark is worn, hidden or missing.
1. Find the mark
Marks are small and often in awkward places. Use your phone camera’s zoom or a magnifying glass, in good light, and check:
- Chains and bracelets — the flat side of the clasp, the tongue of a box clasp, or a tiny tag near the clasp.
- Rings — inside the band, often worn faint.
- Lockets and pendants — the bail (the loop the chain goes through), the inside rim, or the back.
- Bangles — inside, near the hinge or clasp.
- Pocket watches — open the back and look inside the case lid.
Our hallmark guide has photos of where marks usually sit.
2. Read what the mark says
| If it says… | It’s probably… |
|---|---|
| GF, G.F., Gold Filled, 1/20 12K GF, 1/10 10K GF, 14K GF | Gold filled |
| RG, R.G., Rolled Gold, RGP, 1/40 12K RGP | Rolled gold (a close cousin of gold filled) |
| HGP, HGE | Heavy gold plate — thicker than standard plating, but still plating |
| GP, GEP, 18K GP, 18K GE | Gold plated — usually too thin to be worth recovering |
| 9ct, 375, 14K, 585, 18K, 750 on their own | Solid gold |
Watch the trap: “18K GP” is not 18 karat gold — the 18K describes the plating. And on older pocket watches, a case marked “Warranted 20 Years” or “Guaranteed 25 Years” is usually a gold filled case: the warranty referred to how long the gold layer was expected to last.
Not sure what your mark means? Pick it in our Will we buy it? checker.
3. Look closely at the wear
Gold filled has a thick bonded layer, so it wears slowly and evenly — a 50-year-old gold filled chain can still look bright all over. Plated jewellery tends to wear through quickly on the high points: edges, clasps, the back of a ring. If you can see a different-coloured metal (pinkish copper or pale brass) showing through only on the most-rubbed spots after decades of use, that’s consistent with gold filled or rolled gold. Large patches of base metal on a fairly new-looking piece point more towards plating.
4. Try a magnet
Gold filled is built on a brass or copper core, and neither is magnetic. Hold a strong fridge magnet against the body of the piece — not the clasp, which often contains a steel spring. If the magnet grabs it firmly, the piece is likely plated steel. No pull at all doesn’t prove it’s gold filled, but it rules out the most common cheap fakes.
5. Think about when it was made
Gold filled was hugely popular from the late 1800s to around the 1970s, especially for pocket watches and watch chains, lockets, bangles, cufflinks and costume-quality “good” jewellery. Pieces from that era with a warm, even colour and a quality feel are often gold filled or rolled gold. Much modern fashion jewellery, by contrast, is plated.
6. Skip the scratch and acid tests
Home acid kits and scratch tests are designed for solid gold. On gold filled they either test only the surface layer — telling you “gold” when most of the piece is brass — or damage it. Collectable pieces can lose value when scratched. A clear photo of the mark tells a specialist far more.
Still not sure?
Many older pieces are unmarked, or the mark has worn away. That doesn’t mean they’re worthless — it just means they need to be looked at properly. Send us a few clear photos, including a close-up of any marks, and we’ll tell you what you have before you post anything or make a trip. You can also estimate the gold content of marked pieces from their weight.