Most gold and platinum jewelry carries small stamps, usually inside a ring band, on the back of a pendant, or on a clasp or the tongue of a bracelet. A number such as 14K, 585, 18K or 750 tells you the gold purity. PLAT, PT or 950 indicates platinum. A name, initials or a logo is the maker's mark or signature. Read them together: the quality mark says what it is made of, and the maker's mark says who stood behind it. A stamp is a clue, not a guarantee.
Karat and Fineness Marks
Gold purity is stamped in karats or in parts per thousand. The two systems mean the same thing:
- 24K or 999: pure gold, rarely used for jewelry because it is soft.
- 18K or 750: 75 percent gold. Rich in color and common in fine jewelry, including many of the pieces in our vintage jewelry collection.
- 14K or 585: 58.5 percent gold. Harder and more common in everyday jewelry in the United States.
- 10K or 417: 41.7 percent gold, the lowest karat that can be sold as gold in the United States.
- 9K or 375: 37.5 percent gold, often seen on British pieces.
Platinum is marked PLAT, PT, PT950 or 950. Silver is usually 925 or STERLING. Mixed-metal pieces often carry two marks, one for each metal. For instance, this David Webb ring in platinum and 18K yellow gold with black enamel combines both.
The Maker's Mark
In the United States, a karat mark generally has to be accompanied by the registered trademark of the maker or the company that put its name behind the piece. That is why so many American pieces have a small logo or initials next to the 14K or 18K. It is not required that every piece of gold jewelry carry a quality mark at all, but where one appears, the trademark should too. A maker's mark helps trace a piece to a workshop or maker, and with luck to a date.
A maker's mark can be a name, initials in a shape, an animal or a symbol. Some are well documented in reference books and registries. Others belong to small workshops that are hard to trace, which is common with older European pieces.
Signatures and Serial Numbers
A signature is the house name itself, such as Cartier, Tiffany & Co. or Van Cleef & Arpels, usually engraved or stamped in a crisp, consistent style. Many houses also add a serial number, and sometimes a model reference. These can be compared with the maker's records or with known examples. Signed pieces often carry more than one mark: a signature, a metal mark, a serial number and perhaps a country mark. Compare the placement, the size and the quality of the lettering with other pieces from the same house. You can see signed work in our pre-owned and estate jewelry collection, such as this Cartier vintage panthère ring.
European and British Hallmarks
Hallmarks in the strict sense are marks applied by an independent assay office rather than by the maker. British hallmarks usually include the sponsor's mark for the maker, a standard mark for the metal, an assay office mark and a date letter. French pieces, for example, often carry an eagle's head for 18K gold. If a piece carries these marks, they can often be decoded in reference tables. If you are unsure, ask the seller to explain them.
What Marks Cannot Tell You
- They do not prove authenticity. Marks can be added or copied. A convincing stamp on a poorly made piece is a warning sign, not reassurance.
- They do not describe the stones. A metal mark says nothing about whether a gemstone is natural, lab-grown or treated.
- They do not always cover the whole piece. A clasp, pin or screw may be a later replacement and may have its own mark, or none.
- They wear away. Years of wear and polishing can soften a stamp until it is hard to read. Absence of a mark does not by itself mean something is wrong.
That last point matters on older pieces. Our guide to authenticating a David Webb piece shows how design, construction and marks work together as evidence, none of them alone.
How to Read a Mark at Home
- Use a 10x loupe and good light. Hold the piece still and tilt it until the stamp catches the light.
- Write down every mark and its position, then photograph them if you can.
- Check the metal mark against the color and weight of the piece.
- Compare any signature with examples from the maker, paying attention to the font and spacing.
- Ask for help from a jeweler or appraiser if the marks are unclear.
Why It Matters When You Buy
Marks help you compare pieces and ask better questions. Ask the seller to show the marks, to explain what each one means, and to tell you what has been repaired or replaced. A seller who can answer plainly is worth trusting. Our guide to vintage, antique and estate terms covers the other words you will meet in a listing. Every order ships free and insured, and unworn jewelry can be returned within 14 days of delivery.
Frequently asked
What does 750 mean on gold jewelry?
750 means the piece is 75 percent gold, the same as 18K. The number is the gold content in parts per thousand.
Does vintage jewelry always have a hallmark?
No. Not all gold jewelry carries a quality mark, and stamps wear away over the years. Where a karat mark appears on American pieces, a maker's trademark generally should too.
Can a hallmark be faked?
Yes. Marks can be copied or added, so a stamp should be read alongside the design, the construction and the seller's description rather than treated as proof.