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Guide
Jewelry Stamps and Hallmarks Explained
What 10K, 417, 14K, 585, 18K, 750, 925, PT950, GF, and other jewelry stamps mean, and how to read the marks inside a ring or on a clasp.
Where to look
Quality marks are usually stamped inside a ring band, on a clasp or its tag, on an earring post, or on a pendant bail. They are tiny, so a magnifier helps. Many pieces also carry a maker's mark.
Gold
Gold is marked in karats or in parts per thousand: 10K or 417 means about 41.7% gold; 14K or 585 means about 58.3% to 58.5%; 18K or 750 means 75%; 22K or 916 means about 91.6%; and 24K or 999 means pure gold. A karat mark alone does not say the color; white, yellow, and rose gold of the same karat share a mark. Compare karats in 10K vs 14K gold and 14K vs 18K gold.
Silver and platinum
925, STER, or STERLING means sterling silver, 92.5% silver. PT950, PLAT, or 950 PLAT means 95% platinum; PT900 means 90%. See platinum vs gold.
Filled and plated
GF means gold-filled, a thick layer of gold bonded to a base metal, often marked with the fraction of gold such as 1/20 14K GF. GP, GEP, or HGE means gold plated, a much thinner layer. Vermeil is sterling silver plated with gold. These are not solid gold, and the karat in the mark describes only the outer layer.
U.S. rules in brief
In the United States, a piece sold as gold must be at least 10 karat, and federal law requires a quality mark to be accurate and, when one is used, to be accompanied by a registered trademark of the maker or seller. Every product page here names the metal for each option.
Common questions
- What does 585 mean on gold?
- 585 means the alloy is about 58.5% gold, the European mark for 14K gold.
- What does 417 mean on jewelry?
- 417 means about 41.7% gold, which is 10K gold.
- What does 925 mean?
- 925 means sterling silver, an alloy of 92.5% silver.
- Is gold-filled real gold?
- Gold-filled has a real gold layer bonded to a base metal core, but it is not solid gold.