Gold Jewelry Stamps & Hallmarks Explained

By Raphael Weil, GIA Graduate Gemologist & Founder of WeilJewelry   

If you have ever looked closely inside a ring, near the clasp of a necklace, or on the back of a bracelet, you may have noticed tiny numbers and letters such as 585, 750, 14K, 18K, 916, or 999.

These marks can provide valuable information about the purity of the gold, and in some cases, they can also offer clues about where and when a piece of jewelry was made.

However, gold markings can be confusing. A piece may be marked 14K while another is stamped 585, even though both indicate essentially the same gold purity. Vintage and international jewelry can introduce even more unusual marks, including 333, 583, 625, 800, 833, 875, and 958.

This guide explains the most common gold stamps, their karat equivalents, and some of the unusual markings you may encounter on antique, vintage, estate, and modern jewelry.

What Does a Gold Stamp Tell You?

Most gold purity marks use one of two systems: the karat system or the millesimal fineness system.

The karat system divides pure gold into 24 parts. Therefore, 24-karat gold represents essentially pure gold, while 18K gold contains 18 parts gold out of 24.

The millesimal fineness system expresses the amount of pure gold in parts per thousand.

For example:

750 means 750 parts out of 1,000 are pure gold, or 75% gold.

75% gold is equivalent to 18K gold.

This numerical system is especially common on European jewelry, although it is used internationally and should not be thought of as exclusively European.

Quick Guide to Gold Purity Stamps

Here are many of the gold markings you may encounter.

333 = 8K Gold
Contains approximately 33.3% pure gold.

375 = 9K Gold
Contains 37.5% pure gold.

416 or 417 = 10K Gold
Contains approximately 41.7% pure gold.

500 = 12K Gold
Contains 50% pure gold.

583 or 585 = 14K Gold
Contains approximately 58.3% to 58.5% pure gold.

625 = 15K Gold
Contains 62.5% pure gold. This is particularly interesting on antique British jewelry because 15-carat gold was a historical standard that was discontinued in the United Kingdom in 1932.

750 = 18K Gold
Contains 75% pure gold.

800 = 19.2K Gold
Contains 80% pure gold and is particularly associated with Portuguese gold jewelry.

833 = 20K Gold
Contains approximately 83.3% pure gold.

875 = 21K Gold
Contains 87.5% pure gold.

916 or 917 = 22K Gold
Contains approximately 91.6% to 91.7% pure gold.

958 = 23K Gold
Contains approximately 95.8% pure gold.

990 = High-Fineness Gold
Contains 99% pure gold and is equivalent to approximately 23.76 karats.

999 or 999.9 = 24K Gold
Contains approximately 99.9% or 99.99% pure gold and represents the highest-purity gold commonly encountered.

What Does 333 Mean on Gold Jewelry?

A 333 stamp indicates that the jewelry contains 333 parts pure gold per 1,000, or approximately 33.3% gold.

This corresponds to 8-karat gold.

8K gold is less commonly encountered in the United States than 10K, 14K, or 18K gold, but it can be found on European jewelry, particularly vintage pieces.

Because more than two-thirds of the alloy consists of metals other than gold, 8K jewelry may have a noticeably different color and behavior from higher-karat gold.

What Does 375 Mean on Gold Jewelry?

A 375 stamp means that a piece contains 37.5% pure gold, making it equivalent to 9K gold.

9K gold is especially common in the United Kingdom and can also be found in Australia and other markets.

On British jewelry, 375 may appear as part of a larger hallmark containing additional symbols indicating the maker or sponsor and the assay office responsible for testing the piece.

What Does 417 Mean on Gold Jewelry?

A stamp of 417 generally indicates 10K gold.

10-karat gold contains approximately 41.7% pure gold, with the remainder consisting of alloy metals that may include copper, silver, zinc, or other metals.

You may occasionally encounter 416 instead of 417 because the exact mathematical conversion of 10 out of 24 parts is approximately 41.67%.

What Does 585 Mean on Gold Jewelry?

A 585 stamp indicates that the jewelry contains at least approximately 58.5% pure gold and is generally considered equivalent to 14K gold.

This is one of the most common fineness marks found on European and international fine jewelry.

You may also encounter 583, particularly on older jewelry.

Mathematically, 14 divided by 24 equals approximately 58.33%, which explains the 583 designation. The 585 standard contains slightly more gold and became widely adopted as a standardized fineness for 14K jewelry.

Why Do Some Vintage Pieces Say 583 Instead of 585?

The 583 marking is particularly interesting to collectors of vintage jewelry.

It is closely associated with jewelry from the former Soviet Union and other parts of Eastern Europe, where 583 fineness was historically used as a 14-karat standard.

As international standards evolved, 585 became much more common.

Therefore, finding a 583 stamp can sometimes provide a useful clue when researching the origin and age of a vintage piece.

However, a purity stamp alone should never be used to determine the precise age or country of origin of jewelry.

What Does 625 Mean on Gold Jewelry?

A 625 stamp represents 15K gold, containing 62.5% pure gold.

This is a particularly important marking for antique jewelry collectors.

15-carat gold was once an official British gold standard. In 1932, the British 15-carat and 12-carat standards were discontinued and replaced by a 14-carat standard.

As a result, an authentic British piece carrying a 15ct or 625 designation can be an important clue that the jewelry predates that change.

This does not automatically prove the age of an item, but when combined with the complete hallmark, construction methods, style, gemstones, and other characteristics, it can be extremely useful in dating antique jewelry.

What Does 750 Mean on Gold Jewelry?

A 750 stamp indicates 18K gold.

The piece contains 750 parts pure gold per 1,000, or exactly 75% gold.

750 is one of the most recognizable international gold fineness marks and is frequently found on high-end European and Italian jewelry.

You may see:

750

18K

18KT

18ct

All generally indicate 18-karat gold, although the surrounding marks may provide additional information about the maker and origin.

What Does 800 Mean on Gold Jewelry?

The 800 gold mark is less familiar to many American jewelry buyers.

When used as a gold fineness mark, 800 means the alloy contains 80% pure gold, equivalent to 19.2K gold.

This purity is strongly associated with Portuguese jewelry, where 800 gold has a long tradition.

It is worth noting that 19.2K is not exactly the same as 19K. Mathematically, 19K would contain approximately 79.2% pure gold, while 800 fineness contains exactly 80%.

Because 800 is also a purity commonly associated with silver in some countries, the number should always be interpreted in the context of the complete hallmark and the piece itself.

What Does 833 Mean on Gold Jewelry?

A fineness of 833 contains approximately 83.3% pure gold and corresponds to approximately 20K gold.

20K jewelry is considerably less common in the United States than 14K or 18K jewelry but may be encountered on jewelry originating from other parts of the world or on older pieces.

What Does 875 Mean on Gold Jewelry?

A stamp of 875 indicates an alloy containing 87.5% gold, equivalent to 21K gold.

High-karat gold such as 21K is particularly popular in certain parts of the Middle East and Asia.

Because of its high gold content, it generally has a deeper, richer yellow color than 14K or 18K gold.

What Does 916 or 917 Mean on Gold Jewelry?

Both 916 and 917 are associated with 22K gold.

Twenty-two parts out of 24 equals approximately 91.67%, explaining why both numbers may be encountered.

22K jewelry has a very rich yellow appearance and is commonly found in jewelry traditions where high-purity gold is preferred.

What Does 958 Mean on Gold Jewelry?

A 958 stamp represents approximately 95.8% pure gold, or about 23K gold.

Jewelry of this purity is much softer than the 14K or 18K gold commonly used for everyday fine jewelry, but high-karat gold remains popular in certain cultures and styles of jewelry.

What Does 999 Mean on Gold Jewelry?

A 999 stamp indicates gold that is approximately 99.9% pure, commonly described as 24K gold.

You may also encounter 999.9, particularly on investment-grade gold bars and coins.

Although 24K is often described as "pure gold," achieving absolutely 100% purity is difficult in practice. Extremely high-purity gold is therefore commonly expressed as 999 or 999.9 fineness.

Because nearly pure gold is relatively soft, 24K is less commonly used for delicate stone-set jewelry intended for heavy everyday wear.

Why Are There So Many Different Gold Standards?

Gold jewelry has been produced around the world for thousands of years, and different countries developed their own standards, terminology, and hallmarking systems.

The United States commonly uses karat markings such as 10K, 14K, and 18K.

European jewelry frequently uses millesimal numbers such as 375, 585, and 750.

Portugal is particularly known for 800 or 19.2K gold.

Vintage British jewelry may carry discontinued marks such as 12ct or 15ct.

Vintage Soviet jewelry may carry a 583 fineness mark.

Other countries and historical periods have used still other standards.

This is one reason hallmarks can be so fascinating when examining antique and vintage jewelry.

Is a Purity Stamp the Same as a Hallmark?

Not always.

People frequently use the words "stamp" and "hallmark" interchangeably, but technically they can mean different things.

A mark such as 14K, 585, or 750 may simply state the claimed purity of the metal.

A complete official hallmark can contain considerably more information.

Depending on the country and period, a hallmark may include:

A purity or fineness mark

A maker's or sponsor's mark

An assay office mark

A country or national control mark

A date letter

Other official symbols

For example, a complete British hallmark contains more information than simply seeing "750" inside a ring.

Those additional marks can sometimes help identify where a piece was tested, who submitted or manufactured it, and even approximately when it was produced.

What Does KP Mean? Is 14KP Gold Plated?

No.

A mark such as 14KP or 18KP does not ordinarily mean gold plated.

KP stands for Karat Plumb, indicating that the gold was manufactured to meet at least the stated karat fineness.

This is a particularly interesting marking that is frequently encountered on vintage jewelry.

We discuss this subject in greater detail in our guide, "What Does 14KP or 18KP Mean on Gold Jewelry? Understanding Karat Plumb Gold."

Gold Stamps That Do Not Mean Solid Gold

This is where reading jewelry markings becomes particularly important.

A piece marked 14K is very different from a piece marked 14K GP or 14K GF.

GP or GEP

GP generally means Gold Plated.

GEP generally means Gold Electroplated.

These pieces consist primarily of another metal with a layer of gold applied to the surface.

GF

GF means Gold Filled.

Gold-filled jewelry has a layer of gold mechanically bonded to a base metal. It generally contains substantially more gold than ordinary gold-plated jewelry, but it is still not solid gold.

A vintage piece might, for example, carry a marking such as 1/20 14K GF.

RGP

RGP generally means Rolled Gold Plate.

This is another construction in which a layer of gold is bonded to a base metal.

HGE

HGE generally means Heavy Gold Electroplate.

Despite the word "gold" and the presence of a karat number, the piece is not solid gold.

Vermeil

Gold vermeil consists of gold applied over sterling silver.

If a gold-colored piece is stamped 925, the underlying metal is generally sterling silver rather than solid gold.

Does a Gold Stamp Prove That Jewelry Is Real Gold?

No.

A stamp is an important clue, but it is not absolute proof.

Stamps can be forged, added later, incorrectly applied, or misinterpreted.

Conversely, genuine gold jewelry does not always have a visible stamp.

A hallmark can disappear after decades of wear. A ring may have been resized through the original hallmark. A piece may have been manufactured during a period or in a country where marking requirements were different. Very small jewelry may also have been exempt from certain hallmarking requirements.

Professional testing is the best way to determine gold purity when there is any doubt.

Can an Unmarked Piece Still Be Real Gold?

Absolutely.

The absence of a stamp does not automatically mean that jewelry is fake.

This is particularly important when examining antique and vintage pieces.

A hallmark may have worn away, been polished out, disappeared during a repair or sizing, or never been applied in the first place.

Experienced jewelers evaluate the entire piece rather than relying solely on the stamp.

Where Are Gold Stamps Usually Located?

On rings, look inside the shank.

On necklaces and chains, check the clasp or the small tag next to the clasp.

On bracelets, examine the clasp, end links, or interior surface.

On earrings, check the posts, backs, clips, or underside of the earrings.

On pendants, inspect the back and the bail.

These markings can be extremely small, so a 10x jeweler's loupe may be necessary to read them properly.

Can Gold Hallmarks Help Date Vintage Jewelry?

Yes, sometimes.

Hallmarks can be extremely valuable when researching vintage and antique jewelry.

A discontinued gold standard, historical assay-office mark, date letter, maker's mark, or country-specific hallmark can sometimes narrow down when and where an item was produced.

However, hallmarks should be evaluated together with the jewelry's construction, design, gemstone cuts, manufacturing techniques, wear, and overall style.

A single number should never be used by itself to assign an exact date to a piece of jewelry.

Final Thoughts

Gold stamps may look like tiny, insignificant numbers, but they can tell us a remarkable amount about a piece of jewelry.

A 375 stamp indicates 9K gold.

A 417 stamp indicates approximately 10K gold.

A 585 stamp generally indicates 14K gold.

A 750 stamp indicates 18K gold.

An 800 gold mark can indicate 19.2K gold.

A 916 or 917 stamp indicates approximately 22K gold.

And 999 represents approximately 24K or nearly pure gold.

More unusual marks such as 333, 500, 583, 625, 833, 875, and 958 can be especially interesting on vintage and international jewelry.

Most importantly, remember that a purity mark is only one part of the story. When evaluating antique, vintage, or estate jewelry, the complete hallmark, craftsmanship, construction, gemstones, and history of the piece can provide valuable clues that a simple karat stamp cannot reveal on its own.