How to Read the Tiny Numbers Stamped Inside Your Gold
999, 916, 875, 750, 585 — the millesimal fineness stamp tells you exactly how much gold is in a piece. What each number means, where to find it, and what a missing or wrong stamp should tell you.
Turn a gold ring over and look inside the band. Somewhere on that surface, usually in characters small enough to need good light, is a number. It is the most reliable single piece of information about what you are holding.
The millesimal system
Modern hallmarks state purity in parts per thousand. Not carats, not percentages — thousandths. Once you know that, every stamp decodes itself:
| Stamp | Purity | Karat | Where it dominates |
|---|---|---|---|
| 999 or 9999 | 99.9% | 24K | Bars, coins, investment gold |
| 916 | 91.7% | 22K | India, parts of the Gulf |
| 875 | 87.5% | 21K | Egypt, Saudi Arabia, the Levant |
| 750 | 75% | 18K | Europe, designer and gem-set jewellery |
| 585 | 58.3% | 14K | United States, Eastern Europe |
The arithmetic is simply the karat over 24. 21 ÷ 24 = 0.875 = 875. 18 ÷ 24 = 0.75 = 750. Once you see it, you cannot unsee it, and you no longer need to memorise the table.
Where to look
The stamp goes somewhere that will not be worn away by handling and will not spoil the design:
- Rings — inside the band
- Chains and necklaces — on the clasp, or on a small flat tag next to it
- Bangles — on the inner surface, often near the hinge or opening
- Earrings — on the post or the back of the fitting
- Bars and coins — struck into the face along with the refiner's name and often a serial number
Bring a loupe or use your phone camera zoomed in. These marks are frequently under a millimetre.
What else may be stamped alongside
The fineness number is often not alone:
- A maker's mark — the workshop or brand that produced the piece.
- An assay or country mark — a national office's guarantee. Tunisia's ram's head is a well-known example in North Africa; several European countries have their own.
- A date letter — used in some hallmarking systems to record the year of assay.
- "KDM" or "HM" on older Indian pieces — KDM refers to a now-discouraged cadmium solder; HM with a BIS logo indicates modern hallmarked gold.
What a missing stamp means — and does not mean
An unstamped piece is not automatically fake. Genuine reasons exist: it may be antique, from a period or place with no hallmarking requirement; it may be handmade by a small workshop; the mark may simply have worn away on a piece worn daily for thirty years; or a ring may have been resized and lost the stamped section.
But an unstamped piece is a piece with no independent claim about its purity, and you should treat it accordingly. Do not pay a stamped-gold price for unstamped gold on trust alone. Ask the shop to test it in front of you — an electronic conductivity tester takes seconds, and acid testing is standard practice on the counter.
The inverse deserves more caution than it usually gets: a stamp is not proof. Stamps can be forged, and a plated base metal can carry a convincing 750. The stamp is evidence, not a guarantee. On a significant purchase, evidence plus a test plus a receipt naming the karat and weight is what actually protects you.
The check that costs nothing
Before you leave the shop, confirm three things match each other: the stamp on the piece, the karat written on the receipt, and the karat the price was calculated from. A piece sold to you as 21K should be stamped 875 and invoiced as 21K.
Those three agreeing is a good sign. Any two of them disagreeing is a conversation worth having before you pay, not after.
You can check the day's per-gram price for each karat in your own currency on this site before you go, so you walk in already knowing what the metal in the piece is worth.
