Gold hallmarks explained
A gold hallmark tells you the gold content the maker claims. Karat marks count parts of 24 (14K = 14/24), and number marks count parts of 1000: 585 is 14K, 750 is 18K, 916 is 22K and 999 is pure gold. GF, GP and RGP mean gold-filled or plated, not solid gold.
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.
Frequently asked questions
What does 585 or 750 mean on gold?
585 means 585 parts per thousand are gold, the same as 14K. 750 means 75% gold, the same as 18K. See gold hallmarks explained.
What does GF mean on gold?
Gold filled. Under US rules the gold layer must be at least 1/20 of the weight of the metal in the item, so most of it is base metal.