Jewelry Hallmarks Guide: What Every Stamp on Gold & Silver Means

A jewelry hallmark is a small stamp that states what a piece is made of, and you read it in three steps: find the number or karat (925, 585, 14K), check for plating letters (GP, HGE, GF), then treat any initials or logo as a maker's mark. A number such as 925 or 750 tells you the claimed metal purity. Letters such as GP or HGE tell you the piece is plated, not solid gold. Use the tables below to look up any stamp, and see carat vs karat if the two terms are mixed up.

Gold stamps: what each number means

Gold purity is written two ways: karats out of 24 (18K is 18/24) or fineness in parts per 1,000 (750 is 750/1,000). They describe the same thing, so 750 and 18K are the same gold.

What a gold stamp does not prove: it is the maker's claim. It does not say the whole piece is that gold (clasps and posts can differ), and a fake piece can carry a real-looking stamp.

Silver and platinum stamps

Plating letter codes: not solid gold

If a karat is followed or preceded by plating letters, the piece is coated gold, not solid gold. Our guide to sterling silver vs gold plated covers how this affects wear.

Some pieces carry both a silver number and a gold plating code, for example 925 with 18KGP: a sterling silver base with a gold-coloured coating. Both can be honest at once.

Letters and numbers that are not purity marks

Many stamps cannot be decoded from the characters alone. This is where most searches like "14K AJ", "18K CP" or "188 stamp" end up.

• Initials or a logo next to a karat (for example 14K plus two letters) are usually a maker's or brand mark. The same letters can belong to different makers, so we cannot give one meaning for them. Do not assume they mean plating.
• Numbers that are not on the lists above (25, 125, 175, 188, 226, 325 and similar) are not recognised purity marks. They are more likely a size, weight, model or batch number, or part of a maker's mark.
• Country names such as Italy are origin claims. They do not change the metal.
• No stamp at all is common on antique, handmade and very small pieces. It does not mean fake, and it does not mean real.

The letters you can trust to mean something specific are the plating codes in the table above. Anything else needs the maker's identity or a test.

How to check a stamp yourself

1. Find it. Inside ring bands, on clasps or the small tag on a chain, on the back of pendants, on earring posts.
2. Magnify it. A 10x loupe or phone zoom shows whether a stamp is crisp or blurry. Sharp, evenly cut characters are typical of a real stamp, but not proof.
3. Look for wear. A different colour showing at edges or high points suggests a coating over another metal.
4. Check consistency. A stamp that contradicts itself (for example 925 and 14K together) deserves a test.
5. Get it tested. A jeweller can test the metal by acid or electronic testing. For a deeper walk-through, see how to tell if jewelry is real gold.

What a hallmark can and cannot tell you

• A stamp is a claim by the maker. Where an independent testing office applies the mark, as in the UK, it is stronger evidence. Read the UK hallmarking rules for how that system works.
• Rules differ by country: karat marks are normal in the US, fineness numbers in much of Europe, and a full UK hallmark carries a maker's mark, a fineness mark and an office mark.
• Plating stamps are honest: they say the piece is coated. They are a warning, not a defect.
• Nothing on a stamp tells you whether a metal is safe for sensitive skin. See jewelry for sensitive skin.

Guides to individual stamps

• Gold numbers: 750, 585, 417, 375, 14K
• Silver: 925, 925 Italy
• Plating: GP, HGE, 18KGP, gold vermeil
• Comparing: 14K vs 18K, 10K vs 14K, is 18K gold plated worth it, does gold plated tarnish, jewelry glossary

Not sure which you have? See silver plated vs sterling silver.

Frequently asked questions

What are jewelry hallmarks?

Jewelry hallmarks are small marks stamped into a piece that state what the metal is, such as 925 for sterling silver or 750 for 18K gold. Some marks also show who made the piece. A stamp is the maker's claim about the metal, so it is a strong clue but not proof.

How do I identify my jewelry mark?

Look inside a ring band, on the clasp or tag of a chain, or on the back of a pendant or earring post, using a 10x loupe (see our jewelry loupe guide) or phone zoom. Read any number or karat first (925, 585, 14K), then any letters (GP, HGE, GF), then any logo or initials, which are usually a maker's mark. Numbers and plating letters can be decoded with the table above. Logos and initials usually cannot be decoded from the letters alone.

How do you identify hallmarks?

Sort each mark into one of three groups: a purity mark (a number such as 925 or 585, or a karat such as 14K), a plating mark (letters such as GP, GEP, HGE, GF or RGP) or a maker or origin mark (initials, a logo, or a country name). Only the first group tells you the metal content. A plating mark tells you the piece is not solid gold.

Is there an app to identify hallmarks?

A camera or search app can help you read a tiny mark and find lists of similar symbols, but no app can verify the metal in your piece. Only physical testing by a jeweller can do that. Treat any app result for a maker's logo as a lead to check, not an answer.

What does a number like 25, 125 or 188 mean on jewelry?

These are not recognised gold or silver purity marks. The common purity numbers are 333, 375, 417, 500, 585, 625, 750, 833, 875, 916 and 999 for gold, and 800, 835, 900, 925 and 999 for silver. A number outside those lists is more likely a size, a weight, a model or batch number, or part of a maker's mark. Without the maker, it cannot be decoded reliably.

Does 585 mean silver or gold?

Gold. 585 means 58.5% gold, which is sold as 14K. A 585 piece can look silver-coloured because white gold is gold alloyed with white metals. If a silver-coloured piece is stamped 585 and does not feel like gold, have it tested.

Does GP mean real gold?

No. GP means gold plated: a thin layer of gold over another metal. It is real gold on the surface only, not a solid gold piece. GF (gold filled) and HGE (heavy gold electroplate) are also layered, not solid.

What does 925 Italy mean on jewelry?

925 means sterling silver (92.5% silver). Italy is a country-of-origin mark. It does not change the purity, and it does not prove the piece was made there.

Written by the AJLuxe Team. Last updated: October 2026.

Found a stamped piece you no longer wear? Our guide on what to do with old jewelry covers keeping, repairing, donating, recycling and selling.

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