Quick key: Pure-number stamps like 585 or 14K indicate solid-gold purity. Letter stamps like GF, GP, GE, HGE mean the piece is not solid gold. No stamp at all is a red flag — but remember, a stamp is a claim, not proof.
Purity stamps (solid gold)
Gold purity is marked two ways: the US karat system and the European three-digit fineness system. They mean the same thing.
| Karat stamp | Fineness stamp | Gold content |
|---|---|---|
| 10K | 417 / 416 | 41.7% |
| 14K | 585 / 583 | 58.3% |
| 18K | 750 | 75.0% |
| 22K | 916 / 917 | 91.7% |
| 24K | 999 / 9999 | 99.9% |
Warning stamps (NOT solid gold)
These letter codes mean a base-metal piece with gold on the surface. They're legitimate products — just not solid gold, and not worth solid-gold money:
- GF — Gold Filled (thick bonded layer, e.g. 1/20 14K GF)
- GP — Gold Plated (thin electroplate)
- GE / GEP — Gold Electroplate
- HGE — Heavy Gold Electroplate (still plating)
- RGP — Rolled Gold Plate (thinner than gold-filled)
- GV / 925 with a gold mark — often vermeil (gold over sterling silver)
Other marks you'll see
Many chains also carry a maker's mark or a country/assay stamp. A 925 stamp on its own means sterling silver, not gold. "Italy" or a registered maker's mark can be a sign of a reputable manufacturer, but like any stamp it can be faked, so treat it as supporting evidence, not proof.
The stamp is a starting point, not a verdict
Counterfeiters stamp fakes too. Use the hallmark to understand what's being claimed, then confirm it with the hands-on checks in our real-vs-fake guide — magnet, wear-through, and for anything pricey, a professional test.
Frequently asked questions
What does 585 mean on a gold chain?
585 means the chain is 58.3% gold — the European fineness stamp for 14k gold. It's solid-gold purity, equivalent to a '14K' stamp.
What does GF mean on jewelry?
GF means gold-filled: a thick layer of gold bonded to a base-metal core, usually stamped like '1/20 14K GF.' It's durable but not solid gold and has little resale value.
Is a chain real gold if it has no stamp?
Not necessarily. Most real gold is stamped, so a missing stamp is a red flag — but some genuine older or custom pieces lost their stamp, and some fakes are stamped. Verify with a magnet and a professional test rather than relying on the stamp alone.