Jewelry stamps and hallmarks tell you what metal a piece is made of and how pure it is. Numbers show parts per thousand: 925 is sterling silver, 585 is 14K gold and 750 is 18K gold. Letters show construction: GF means gold filled, GP means gold plated and HGE means heavy gold electroplate, all of which are gold over another metal.
Use the charts below to decode a mark in seconds, then check the maker's trademark beside it.
Jewelry Stamps vs Hallmarks: What Is the Difference?
A jewelry stamp is a mark the maker applies, while a hallmark is a set of marks applied by an independent assay office after testing the metal. In the US, most marks are maker's stamps; in the UK, hallmarks are a legal requirement above set weights.
Under the National Gold and Silver Stamping Act, any US business that stamps a quality mark such as 14K or 925 must also apply a registered trademark to the piece (15 U.S.C. 297). The World Gold Council notes that US caratage does not have to be marked on the piece at all, so a missing stamp is legal.
A UK hallmark has three compulsory parts: a sponsor's mark (the maker or importer), a fineness mark and an assay office mark. The London Assay Office notes that the date letter is no longer compulsory and that the rules come from the Hallmarking Act 1973. Read the full rule in the Stamping Act trademark section and the World Gold Council hallmark guide.
Gold Stamps: Karat Marks and Purity Numbers
A gold stamp shows purity either in karats (K or KT) or as a three digit number in parts per thousand. Pure gold is 24 parts out of 24, so 14K means 14 parts gold and 10 parts other metals.
| Karat stamp | Number stamp | Gold content |
|---|---|---|
| 8K | 333 | 33.3% |
| 9K | 375 | 37.5% |
| 10K | 417 | 41.7% |
| 14K | 583 or 585 | 58.3% to 58.5% |
| 18K | 750 | 75% |
| 22K | 916 or 917 | 91.6% to 91.7% |
| 24K | 999 | 99.9% |
GIA lists gold alloys from 8K (333) to 22K (917) and notes that 14K may be stamped 583 or 585 (GIA guide to gold karats). The UK recognizes 375, 585, 750, 916, 990 and 999 as gold fineness marks (London Assay Office on hallmarks). US law allows real fineness to fall only three parts per thousand below a gold mark, or seven once solder is included (15 U.S.C. 295).
Gold Filled, Gold Plated and Vermeil Marks: GF, GP, GEP, HGE
Letters after a karat number mean the piece is not solid gold: GF, RGP, GP, GEP and HGE all describe a layer of gold over another metal. The FTC Jewelry Guides set the minimums behind these terms.
| Mark | Stands for | FTC minimum |
|---|---|---|
| GF, 1/20 14K GF | Gold filled | At least 10K gold, at least 1/20 of the total metal weight |
| RGP, 1/40 12K RGP | Rolled gold plate, gold overlay | At least 10K gold, mechanically bonded; the fraction of the weight must be stated |
| GEP, GP | Gold electroplate (GP is common shorthand for gold plated) | At least 10K gold, at least 0.175 microns thick for gold electroplate |
| HGE | Heavy gold electroplate | At least 10K gold, at least 2.5 microns thick |
| Vermeil | Gold over sterling silver | At least 10K gold, at least 2.5 microns, over sterling |
The FTC Jewelry Guides require heavy gold electroplate to measure at least 2.5 microns of fine gold equivalent, about 14 times the 0.175 micron minimum for standard gold electroplate (16 CFR 23.3). The HGE mark therefore signals a much thicker layer, though still only a surface coating over another metal.
A mark like 1/20 14K GF reads as "gold filled with 14 karat gold making up one twentieth of the metal weight." The thresholds come from 16 CFR 23.3 and the vermeil rule in 16 CFR 23.4. For how these finishes wear in real life, read gold filled vs gold plated vs vermeil.
Silver Stamps: 925, Sterling, 999 and EPNS
A 925 stamp means sterling silver, which is at least 92.5% pure silver. The FTC treats "sterling" and "solid silver" as misleading for anything below 925 parts per thousand, and "coin silver" requires 900 (16 CFR 23.5).
| Stamp | Meaning |
|---|---|
| 999 | Fine silver, 99.9% pure |
| 958 | Britannia silver, a UK fineness standard |
| 925, .925, STERLING, STER | Sterling silver, at least 92.5% |
| 900, COIN | Coin silver, at least 90% |
| 800 | 80% silver, common on older European pieces |
| EP, EPNS | Electroplated (EPNS: electroplated nickel silver), not solid silver |
The UK recognizes 800, 925, 958 and 999 as silver fineness marks. US law allows a silver piece to fall no more than four parts per thousand below its mark (15 U.S.C. 296). A mark such as 925 Italy pairs the sterling number with the country where the piece was made.
Platinum and Palladium Stamps
Platinum is usually marked PT, PLAT or PLATINUM, often with a number such as 950 or 900. The FTC says an item should be at least 95% pure platinum to be called platinum without qualification (FTC guide to buying precious metal jewelry).
In the UK, the recognized platinum finenesses are 850, 900, 950 and 999, and the minimum legal fineness for palladium is 500. Under 16 CFR 23.6, US pieces with 850 to 950 parts per thousand platinum must show the number before the mark, as in 900Pt or 850Plat. Because both metals are white, white gold, rhodium plated metals and silver can look similar, so the stamp is the quickest way to tell them apart.
How to Identify a Jewelry Mark
To identify a jewelry mark, find it, magnify it and read it in three parts: the metal number, any letters after it and the maker's mark. A 10x jeweler's loupe and good light are all you need.
- Check the usual spots: inside a ring band, on the clasp or the small tag beside it, on the back of a pendant bail and on earring posts.
- Read the number first (925, 585, 750) to get the metal and purity.
- Look for letters after it (GF, GP, HGE, EP) that signal a layer rather than solid metal.
- Find the maker's trademark or, on UK pieces, the sponsor's and assay office marks.
- For antique maker's marks, search a specialist maker's mark archive or ask a jeweler.
Stamps can be worn away by resizing or polishing, and they can be faked. A karat mark with no trademark beside it is a red flag in the US, and an independent acid or XRF test at a jeweler is the only way to confirm the metal.
Why Most Fashion Jewelry Has No Stamp
Most fashion jewelry has no metal stamp because it is plated or made from base metals, and stamps are mainly used for precious metal content. A missing stamp on an affordable piece is normal and not a sign of anything wrong.
EVRY Jewels focuses on affordable fashion jewelry, so read each product page for the exact finish rather than looking for a stamp. Browse bracelets, necklaces and rings, or start with a fine chain like the Box Chain Bracelet. To keep plated pieces looking their best, read does gold plated jewelry tarnish and the gold plated jewelry care guide, and for ring finishes compare 14k vs 18k gold plated rings.
Frequently Asked Questions About Jewelry Stamps
What does 925 mean on jewelry?
A 925 stamp means the piece is sterling silver, made of at least 925 parts per thousand (92.5%) pure silver, with the rest usually copper. The FTC Jewelry Guides treat the word sterling as misleading for anything below that level, and US law allows only a four parts per thousand shortfall. Look for a maker's trademark next to the 925, since the mark alone can be faked on base metal jewelry.
What does a 10K stamp mean on jewelry?
A 10K stamp means the piece is 10 karat gold: 10 parts gold out of 24, or about 41.7% gold, often also stamped 417. The rest is alloy metals such as silver, copper or zinc, which make 10K harder than higher karats. If letters follow the mark, such as 10K GF or 10K GP, the piece is gold filled or gold plated over another metal, not solid 10 karat gold.
What does 14K GF or 1/20 14K GF mean?
14K GF means gold filled with a 14 karat gold layer. Under the FTC Jewelry Guides, gold filled jewelry must use gold of at least 10 karats that makes up at least 1/20 of the total metal weight, so 1/20 14K GF states exactly that ratio. Gold filled is far thicker than standard plating, but the core is still another metal. Treat it as durable gold layered jewelry, not solid 14K gold.
What does HGE mean on jewelry?
HGE stands for heavy gold electroplate. The FTC Jewelry Guides require at least 2.5 microns of gold of 10 karats or more for this term, compared with 0.175 microns for regular gold electroplate. A mark like 18K HGE describes the karat of the plating layer only. The piece underneath is another metal, so HGE jewelry needs the same gentle care as other plated jewelry to keep the surface intact.
What does the 8 stamp on jewelry mean?
An 8K stamp, or the number 333, usually means 8 karat gold, which is 8 parts gold out of 24, or 33.3% gold. GIA lists gold alloys from 8K (333) up to 22K (917), so 8K sits at the low end of the range. A lone 8 with no K may also be part of a different mark, such as 800 silver, so read the full stamp with a loupe.
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