Jewelry Hallmarks and Stamps Explained

A stamp reading 925 tells you the alloy is 92.5 percent silver. It does not tell you the piece is solid, that the stones are what the listing says, or that the construction will survive daily wear. Hallmarks and stamps are compositional statements, and understanding exactly what they assert is what turns them from reassurance into useful evidence — along with knowing what still has to be checked by other means.

Last updated: October 11, 2026

What does 925 stamped on jewelry mean?

It means the metal is sterling silver: 92.5 percent silver by weight, with the balance usually copper or a similar addition.

The number is a fineness mark, sometimes accompanied by the word sterling or the letters STG. Equivalent marks exist for other metals: 999 for fine silver, 750 for 18K gold, 585 for 14K, 417 for 10K, and 950 for platinum. Each states the proportion of the precious metal in the alloy, and nothing else.

Fineness marks are the most common form of hallmarking in export markets. In some countries a separate, government-administered assay office applies its own marks after testing, which carries more weight than a manufacturer’s stamp because the piece has been verified rather than simply labelled.

What hallmarking actually is

An independent test followed by a mark, or a manufacturer’s declaration in the form of a stamp.

In the traditional system, a piece is submitted to an assay office, the metal content is tested, and the office strikes a mark recording the fineness, sometimes with a maker’s mark and a date letter. That process is verification. In most other markets, the manufacturer stamps the piece and is legally responsible for the accuracy of the claim, which is a declaration rather than a verification.

Both systems are legitimate. The difference matters to a buyer because a maker’s stamp is only as reliable as the maker, while an assay mark has been produced by a third party.

The marks you will actually see

Fineness marks and their meanings.

Mark	Metal	Fineness	Typical use
999 / fine silver	Silver	99.9% silver	Bullion, some traditional jewellery; too soft for most settings
925 / sterling	Silver	92.5% silver	The standard silver jewellery alloy
417 / 10K	Gold	41.7% gold	Hard-wearing everyday rings
585 / 14K	Gold	58.5% gold	Fine jewellery and settings
750 / 18K	Gold	75.0% gold	Higher-value pieces; deeper colour
950 / PT	Platinum	95.0% platinum	Rings and high-value settings
Pd / 950Pd	Palladium	95.0% palladium	Alternative white metal

What a stamp does not tell you

Four things that buyers routinely assume it confirms.

It does not confirm that the piece is solid rather than plated, because a plated article can legally carry a fineness mark if the plating meets the threshold in that market — and some markets require the word plated alongside it. It says nothing about the stones, their identity, origin or treatment. It does not confirm the weight, which is the fastest way to detect hollow construction. And it does not indicate who made the piece or where.

The practical check that catches most of this is weight against dimensions: a hollow or plated piece of a given size weighs noticeably less than a solid one.

How to read a full hallmark

Four elements, not always all present.

A complete traditional hallmark can carry the sponsor’s or maker’s mark, the fineness mark, the assay office mark and a date letter. Most export jewellery carries only the fineness mark plus a country of origin or a maker’s initials. Where several marks are present, read them in that order: the maker identifies who is accountable, the fineness states the alloy, and the office mark indicates who verified it.

Where a piece carries no mark at all, that is not proof of anything either. Some handmade and vintage pieces are unmarked, and some very small components are below the weight threshold at which marking is required.

Plated metals and how they are marked

Plating is a legitimate construction and should be marked as such.

A gold-plated or rhodium-plated piece should be described as plated, and in regulated markets the description has to state it. The manufacturing standard that applies to electroplated silver coatings defines thickness grades, which is why a plating specification is worth asking for rather than assuming: a heavier deposit lasts considerably longer at the contact points of a ring or the clasp of a bracelet. The distinction is covered in our notes on rhodium plating on silver. The broader test for silver is set out in the guide to telling whether silver is real, and fineness grades themselves in our explanation of silver purity.

Country differences worth knowing

The rules are not the same everywhere, which is why export documentation matters.

Some markets require independent assay and a specific set of marks before a piece can be described as precious metal. Others rely on manufacturer declaration with legal liability attached. A third group requires the fineness mark plus an indication of the responsible business. For a buyer importing, the practical consequence is that a piece legal in one market may need additional marking to be sold in another, which is worth confirming before a large order rather than after.

Our own exports are marked to the fineness standard of the destination market and the marks are recorded on the specification sheet for each shipment.

What to check before buying

Five steps, in order.

Look for a fineness mark and confirm it matches the metal ordered. Check whether the piece is described as plated, and ask for the plating specification if it is. Compare the stated weight against the dimensions. Check the stones against their documentation, since the hallmark says nothing about them. And where the piece is high value, ask for the assay or certification documentation that accompanies the shipment.

None of the five is difficult, and together they cover everything the stamp leaves open.

Sources and further reading

• Assay Office — hallmarking standards and mark types
• The Silver Institute — sterling silver composition
• ASTM B700 — electrodeposited silver coating specification
• CIBJO Blue Books — precious metal nomenclature and disclosure
• International Gem Society — jewellery materials reference
• GIA Report Check — verifying stone documentation, which hallmarks do not cover

Next step: Send us the marks on a piece and the specification you were given, and we will tell you what the marks confirm and what still needs checking before purchase or import. Ready-stock pieces, marked specifications and OEM programmes are all available. Contact vinico@zkzdiamonds.com or WhatsApp +86 135 3037 8229.

Part of our 925 sterling silver jewelry guide.