How to Read Gold Hallmarks and Purity Stamps
What the BIS hallmark, HUID code and numbers like 585, 750 and 916 mean — and how to check them.
The BIS hallmark (India)
Gold jewelry hallmarked in India carries three marks, usually laser-engraved inside a ring or on a clasp:
- The BIS logo — the standard mark of the Bureau of Indian Standards.
- The purity grade in karats and fineness, e.g. 22K916 or 18K750.
- A unique 6-character HUID (Hallmark Unique ID) for that individual piece.
Fineness numbers explained
Fineness is the gold content in parts per thousand. The same numbers are used in many countries, so they are a quick way to read any piece:
| Karat | Fineness stamp | Pure gold |
|---|---|---|
| 9K | 375 | 37.5% |
| 14K | 585 | 58.5% |
| 18K | 750 | 75% |
| 22K | 916 | 91.6% |
| 24K | 999 / 995 | 99.9% / 99.5% |
Silver stamps
Sterling silver is stamped “925” (92.5% silver). You may also see “STERLING” or “STER”. Fine silver is 999.
How to check a hallmark
- Use a jeweler’s loupe (10×) to read small stamps.
- In India, the HUID can be verified with the BIS CARE app.
- Keep your certificate of authenticity and stone certificates with your purchase records — insurers and resellers ask for them.