Some of the most interesting details on an old jewel are also the smallest.
Turn a ring over, peek at the back of a clasp, or look inside a bangle, and you may find a row of tiny stamps. These are hallmarks and maker's marks. They can tell you what a piece is made of, who made it, where it was tested, and sometimes even the year it was made.
This guide is a soft, simple introduction to reading those marks. We will look at what the most common numbers and symbols mean, how marks differ from country to country, ten higher-ticket pieces from the Boylerpf collection with lovely marks to learn from, and a few easy tips for looking at marks yourself.
What Hallmarks Are, in Plain Words
A hallmark is a little promise stamped into metal. In many countries, gold, silver, and platinum jewelry was sent to an official assay office, where the metal was tested and then marked to show its purity. The word itself comes from Goldsmiths' Hall in London, where pieces were tested and marked for centuries.
England has one of the oldest systems in the world. Hallmarking there began around 1300, and a full English set can include a maker's or sponsor's mark, a standard mark for the metal, a town mark for the assay office, and a date letter. London uses a leopard's head, Birmingham an anchor, and Edinburgh a castle.
Other countries have their own lovely traditions. France uses tiny animal heads, Portugal uses symbols such as the Porto cat's head, and Russia used numbers called zolotniks. The United States never had a national hallmarking system, so American jewelry usually shows a simple karat stamp, often with a maker's name.
The Most Common Marks and What They Mean
You do not need to memorize everything to enjoy hallmarks. A few simple marks will take you a very long way.
- Karat marks for gold. 9K, 10K, 14K, 18K, and 22K tell you how much of the metal is pure gold, out of 24 parts. 18K means 18 parts gold out of 24, or 75 percent.
- Fineness numbers for gold. 375 is 9K, 417 is 10K, 585 is 14K, 750 is 18K, and 916 is 22K. These numbers show parts of pure gold per 1,000.
- Silver marks. 925 or "Sterling" means 92.5 percent silver. 800 is a common European silver standard. The English lion passant is the classic sterling mark.
- Platinum marks. "Plat," "Pt," "PT950," "900," or "950" all point to platinum, the strong white metal that made Edwardian and Art Deco jewelry so delicate and bright.
- Maker's and designer marks. Initials, names, or small logos, such as "Tiffany & Co.," "Cartier," or a tiny symbol, tell you who made the piece.
- Plated and filled marks. "GF," "1/20 12K GF," "RGP," "GP," and "HGE" mean a piece is gold-filled or gold-plated, with a layer of gold over another metal. These pieces can be very pretty, they are simply a different thing from solid gold.
"A hallmark is a tiny signature from the past, a quiet note that says who made this, and how carefully it was made."
Ten Pieces with Marks Worth Reading
Here are ten higher-ticket pieces from the Boylerpf collection, each with a mark that tells a little story. Every one is a one-of-a-kind piece, so the product page always has the latest details and close-up photos.
The Antique Georgian 18K Gold Enamel Mourning Ring Band is a lovely place to start, because it carries a complete set of English hallmarks. It is made of 18K yellow gold with a band of black enamel and gold lettering, framed above and below by little repoussé flowers.
Inside, the hallmarks confirm 18K gold and show the maker's initials, JG. The ring is also inscribed "Obit 6 Oct 1823 Alt 46," a tender remembrance of someone who passed away at age 46. Together, the marks and the words tell you who made it, what it is made of, and the moment it was made for.
On an English piece, look for a group of small stamps in a row: the maker's initials, a mark for the gold standard, a town mark, and a date letter. Even when they are tiny, they are often surprisingly crisp under a loupe.
The Vintage 9K Gold Curb Link Necklace English Hallmarked is a friendly example of a modern-style purity mark. It is English hallmarked "375," which simply means 375 parts gold in 1,000, or 9 karat. It also carries the sponsor's mark THB, the initials of the firm that sent it to be tested.
Thick, solid curb links give it a rich weight, and an oversized bolt ring clasp adds a classic finish. It is a chain that suits everyone and looks just as good alone as layered.
A three-digit number is a fineness mark, telling you how many parts in 1,000 are pure metal. 375 is 9K, 585 is 14K, 750 is 18K, and 916 is 22K.
The Art Deco Platinum 1 Carat European Diamond Ring shows how platinum was often marked in the 1920s. Inside the band you will find "Plat" along with the initials HB, a maker's mark.
A bright European-cut diamond sits at the center, surrounded by sixteen single-cut diamonds in a stepped pattern with soft milgrain edges. The total diamond weight is about 1 carat, and the whole ring has that crisp, geometric charm Art Deco is loved for.
Platinum may be stamped "Plat," "PLAT," "Pt," "PT950," or simply "950." Each of these tells you the ring is made of this strong, naturally white metal.
The Vintage French Tanzanite & Diamond Ring in 18K White Gold carries an 18K mark and a small fleur-de-lis stamp on its band, a sweet reminder of its French roots. French jewelry is famous for its tiny, beautifully designed marks, which often take the shape of animal heads or symbols.
A vivid oval tanzanite of about 1.25 carats is framed by a rectangle of illusion-set diamonds and lifted on a pierced, ribbed mounting. It is bold, cheerful, and full of mid-century glamour.
For 18K gold, France has used a little eagle's head since 1838. French marks are often very small and placed on a clasp, a band, or a jump ring, so a loupe and good light really help.
The Vintage Portuguese 19.2K Gold Bracelet with Turquoise has one of the most charming hallmarks in the collection. Its clasp bears the Portuguese Porto cat's head mark, the number 800, and a maker's mark. In Portugal, 800 means 19.2 karat gold, which explains the deep, warm color.
Hallmarks like these can even help with dating. This combination places the bracelet between 1938 and 1984. The links have smooth, rounded edges with tiny flowers, and the decorative box clasp is set with a bright turquoise cabochon.
The same number can mean different things in different places. In Portugal, 800 on gold means 19.2K. On a piece of European silver, 800 means 80 percent silver. Context, and a quick test, tell you which one you are looking at.
The Victorian Russian 4CT Diamond Navette Ring, Antique Gold is finished with original Russian hallmarks on the back of the band. Russian gold was measured in zolotniks rather than karats, so a mark of 56 is about 14K, and 72 is about 18K.
About 4 carats of old European and old mine-cut diamonds fill a long, elegant navette shape, with a rectangle-cut diamond at the heart. Open-backed settings let the light pour through, and scrolling shoulders flow into a double band.
Russian marks are often tiny and very detailed, and many show a small profile of a woman in a traditional headdress, known as the kokoshnik mark. A good photo or a closer look under magnification is the best way to enjoy them.
The Cartier Love Ring 18K Yellow Gold Diamond Band 0.23ct shows how the great jewelry houses sign their work. It is marked "Cartier," "750" for 18K gold, "55" for the ring size, and a serial number, all neatly engraved inside the band.
Three brilliant diamonds, about 0.23 carats in all, sit among the famous screw motifs on a polished 5.5mm band. It comes with its original Cartier box, which is a lovely bonus for a collector or a gift.
Fine houses often add a signature, a fineness mark, and a serial number. Clean, even engraving that matches the house style is a good sign of a well-made, genuine piece.
The Vintage Tiffany & Co. 18K Gold Diamond Bangle Bracelet is signed Tiffany & Co. and marked 18K. For American jewelry, a maker's name next to a karat stamp is the classic pairing, since the United States never had a national hallmarking system like Britain.
The hinged bangle has diamond-set stations framed by fluted gold bars, with about .75 carats of round brilliant diamonds in all. A side-lock closure and safety catch keep it secure on the wrist.
On American jewelry, you will usually see a karat mark such as 10K, 14K, or 18K, often with a maker's name or logo. These marks are simpler than European ones, but a well-known signature adds lovely history.
The Vintage 18K Gold Chain Diamond Cuban Link Ring, 14.4 Grams is a vintage Pomellato design, marked "750," "18K," and "Pomellato." Italian jewelry usually carries the 750 fineness mark, and many pieces also have a small star-shaped registration mark with a number and a province code.
A flexible flat curb chain forms the wide band, with pavé diamonds set in white gold flowing across the front. It is bold and fluid, and it looks wonderful on any hand.
The Ilias Lalaounis 18K Gold Byzantine Ruby Sapphire Emerald Ring is stamped "A21 750" and carries the maker's distinctive fish mark. It is a wonderful example of how a hallmark can be both a quality mark and a small work of art.
This circa 1960s ring comes from Lalaounis' Chryotectonemata Collection, inspired by Byzantine tiaras. A mosaic of bezel-set rubies, sapphires, and emeralds covers its tall, scalloped face, with fine milgrain detail all around.
A designer's mark is often the first thing collectors look for. Learning a few favorite makers' marks is a fun and easy way to grow your eye.
A Simple Field Guide to Reading Marks
Reading marks is a gentle skill that grows with practice. Here is a quick guide to what you might find and what it can tell you.
Every piece at Boylerpf is personally sourced and authenticated, and metals are tested when marks are missing or hard to read. If you would like a closer photo of a hallmark or have a question about what a mark means, you are always welcome to ask. Email alicia@boylerpf.com or call 701-535-0798.
Common Mix-Ups, Cleared Up
"If a piece has no hallmark, it cannot be real gold."
Many antique pieces were never marked, especially small jewels made before marking was required. A simple metal test tells you exactly what you have.
"A stamp always means the same thing everywhere."
Marks depend on the country. In Portugal, 800 on gold means 19.2K, while on European silver, 800 means 80 percent silver. A little context goes a long way.
"Higher karat is always better."
Each karat has its charm. 22K glows with deep color, 18K is rich and classic, and 14K and 9K are a little harder for everyday wear.
Easy Tips for Looking at Marks Yourself
You do not need special training to start reading marks. A few small tools and a little patience are all it takes.
- Use a 10x loupe. A small jeweler's loupe is inexpensive and makes tiny marks easy to see. Hold it close to your eye and bring the jewel toward it.
- Find good light. Daylight from a window or a soft desk lamp shows the edges of a stamp best.
- Tilt slowly. Stamps are tiny dents in the metal, so turning the piece a little can make them suddenly appear.
- Take a photo. A phone camera with zoom can capture a mark you can then enlarge and look at calmly.
- Keep a little list. Write down marks you have learned. Over time, you will start recognizing them at a glance.
A small habit worth keeping: snap a photo of each mark for your records, and ask your jeweler to work away from the hallmarks if a ring is ever resized. For more ways to buy with confidence, read 10 Signs You're Buying Authentic Antique Jewelry.
Hallmarked & Signed Jewelry from Boylerpf
Each link below leads to a piece featured in this guide. Antique and vintage jewelry is one of a kind, so the product page always has the latest details and close-up photos.
Common Questions
A hallmark is an official mark stamped into gold, silver, or platinum, often after the metal has been tested by an assay office. It usually shows the purity of the metal and, in some countries, where and when the piece was tested. A maker's mark, which shows who made the piece, often appears alongside it.
They are fineness marks that show how many parts of pure gold are in 1,000 parts of metal. 585 means 14K gold, and 750 means 18K gold. You may also see 375 for 9K, 417 for 10K, and 916 for 22K.
Not always. Many antique pieces were never marked, especially smaller jewels and pieces made before marking was required. Marks can also soften with years of wear. When marks are missing, a simple metal test by an experienced jeweler confirms the material.
Look for marks such as GF, 1/20 12K GF, RGP, GP, HGE, or EP. These mean a layer of gold has been bonded or plated over another metal. Gold-filled and plated pieces can be lovely, they are simply different from solid gold.
A clear signature from a respected maker, such as Tiffany & Co., Cartier, or Lalaounis, adds history and collectibility. Many fine houses also add a fineness mark and a serial number, and original boxes or papers are a lovely bonus.
Boylerpf is always happy to help. Every piece is personally sourced and authenticated by the shop, and you are welcome to reach out with any questions about hallmarks or maker's marks. Email alicia@boylerpf.com or call 701-535-0798.
Keep Reading
More from the Boylerpf journal on eras, authenticity, and finding pieces you love.
Pick up a loupe, turn a jewel over, and enjoy the little stories stamped into the metal.
Browse Estate, Vintage & Antique Jewelry at Boylerpf →