Gold hallmarks explained
The small stamp on a clasp or inside a ring tells you how much gold the maker says is in the piece.
| Mark | Gold | Typical use |
|---|---|---|
| 24K, 999, 9999 | 99.9–99.99% | Bullion bars and coins, some jewelry |
| 22K, 916, 917 | 91.6% | Traditional jewelry, some bullion coins |
| 18K, 750 | 75% | Fine jewelry, watch cases |
| 14K, 585 | 58.5% | Rings, chains, everyday jewelry |
| 10K, 417 | 41.7% | Lower-cost jewelry in the US |
| 9K, 375 | 37.5% | Lower-cost jewelry, common in the UK |
| GF, RGP, GP, HGE, GEP | thin layer only | Gold-filled or plated: not solid gold |
Karat marks and number marks
There are two common ways to show gold content. American jewelry usually uses karats: 14K means 14 parts gold out of 24. European jewelry usually uses parts per thousand: 585 means 585 parts gold out of 1000. They describe the same thing: 14K and 585 are both about 58.5% gold.
Gold-filled and gold-plated marks
If the karat mark is followed by GF, RGP, GP, HGE or GEP, the item is not solid gold. Under US rules, “gold filled” requires a layer of gold alloy that is at least 1/20 of the weight of the metal in the whole item, and “rolled gold plate” at least 1/40 (16 CFR 23.3). Electroplated items have a much thinner layer still. For melt value, these items are worth only a small fraction of solid gold, and many buyers will not take them.
How accurate is a stamp?
US law allows a small tolerance. Under the National Stamping Act, as summarized in the FTC Jewelry Guides, gold articles without solder may be up to 3 parts per thousand below the stamped fineness, and up to 7 parts per thousand if the tested part contains solder (16 CFR 23.3, note 32). Fake stamps exist too, so test pieces you are unsure about.
Where to find the stamp
- Rings: inside the band.
- Chains and necklaces: on the clasp or on a small tag next to it.
- Earrings: on the post or the back.
- Watches: inside the case back.
Use a magnifying glass or your phone camera zoomed in. If the stamp is worn away, a buyer can test the metal. See how to test gold at home.