Gold Jewelry Stamps: What 10K, 14K, 585 and 750 Mean
Decode gold jewelry stamps: karat marks, millesimal numbers, GF, GP, RGP and HGE plating marks, maker's marks and what an unmarked piece might be.
By Ayoub Farid · · 2 min read
Tiny stamps inside a ring or on a clasp tell you how much gold a piece contains — or whether it's only plated. Knowing these marks lets you separate scrap from treasure in seconds.
Karat marks
Karat (K or KT) measures gold purity out of 24 parts:
| Stamp | Gold content |
|---|---|
| 9K | 37.5% |
| 10K | 41.7% |
| 14K | 58.3% |
| 18K | 75% |
| 22K | 91.6% |
| 24K | 99.9% (pure) |
Millesimal (number) marks
Many countries use parts per thousand:
| Stamp | Equivalent |
|---|---|
| 375 | 9K |
| 417 | 10K |
| 585 | 14K |
| 750 | 18K |
| 916 | 22K |
| 999 | 24K |
Plated and filled marks — not solid gold
- GF — gold filled: a thicker layer of gold bonded to base metal. More durable than plate, but not solid.
- GP / GEP — gold plated / gold electroplated
- RGP — rolled gold plate
- HGE — heavy gold electroplate
- "1/20 12K GF" — fraction of weight that's 12K gold, the rest base metal
- Vermeil — gold over sterling silver
Other marks you'll see
- Maker's or brand marks — can add value beyond the metal
- Country hallmarks — British and some European gold has hallmarks like silver
- PLAT / PT950 — platinum
- 925 alongside gold color — gold-plated silver
Unmarked gold
Older pieces, hand-made jewelry and items from some countries may be unmarked, and marks wear off. A jeweler's acid or electronic test confirms purity. See how to tell real gold.
Beware fake stamps
Stamps can be faked. A "14K" mark on a piece that's magnetic, discolored where it's worn, or suspiciously light deserves testing.
Scan your jewelry
Scan pieces with AntiqueIQ for a quick identification, era and estimated value range — then check the stamps under a loupe. Related: antique jewelry identification.
Frequently asked questions
Is 585 gold real?
Yes. 585 means 58.5% gold, the same as 14K.
Is gold filled worth anything?
It has some value and can be collectible in vintage pieces, but far less than solid gold.
What does 750 mean on jewelry?
It's 18K gold: 75% pure gold.