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A hallmark is an official mark that confirms the purity of a precious metal after independent testing. In India, hallmarking is run by the Bureau of Indian Standards (BIS) under the Government of India. This guide explains what a BIS hallmark shows, how to check one, and what the purity of your Zarna Jewels piece means.
What a BIS hallmark shows
Since 1 July 2021 a BIS hallmark on gold jewellery has three parts:
- The BIS logo: the standard mark of the Bureau of Indian Standards.
- The purity grade: the karat and fineness, for example 18K750 or 14K585.
- A 6-digit HUID: a unique alphanumeric Hallmark Unique Identification code given to each hallmarked piece.
Hallmarking of gold jewellery became compulsory in India in June 2021, first in 256 districts and later in more. Since 1 April 2023, hallmarked gold jewellery must carry a 6-digit HUID.
How to check a hallmark
- Look for the marks with a magnifying glass, usually inside a ring band or on a clasp.
- Download the free BIS CARE app from the official app stores.
- Enter the 6-digit HUID in the app’s “Verify HUID” section to see the purity, the type of article and the testing centre.
Gold purity explained
| Karat | Pure gold | Fineness | Typical use |
|---|---|---|---|
| 24K | 99.5% and above | 995 / 999 | Coins and bars; too soft for jewellery |
| 22K | 91.6% | 916 | Traditional Indian gold jewellery; too soft for diamond settings |
| 18K | 75% | 750 | Fine and diamond jewellery |
| 14K | 58.5% | 585 | Everyday diamond jewellery |
| 9K | 37.5% | 375 | Hard-wearing, affordable gold jewellery |
Zarna Jewels makes gold jewellery in 9K, 14K and 18K. All three are BIS hallmarking grades for gold (375, 585 and 750), so every gold piece can carry the BIS mark with its fineness. Our metal guide compares the three purities.
Silver purity explained
Sterling silver contains 92.5% pure silver and is marked 925. Silver can also be hallmarked by BIS, which confirms its fineness; in India this is currently voluntary rather than compulsory.
Hallmarks and diamonds
A hallmark confirms the purity of the metal only. Diamonds are graded separately by gem laboratories: you can add an IGI report for your laboratory-grown diamond at checkout, which records its 4Cs and origin. See our diamond guide.
Why hallmarking matters
- Assurance: you get the purity you pay for, tested by an independent centre.
- Traceability: the HUID links the piece to its hallmarking record.
- Resale and exchange: hallmarked gold is easier to value, exchange or sell.
Frequently asked questions
Is hallmarking compulsory in India?
For gold jewellery, yes: hallmarked gold sold by registered jewellers must carry the BIS logo, purity grade and 6-digit HUID. Hallmarking of silver is voluntary.
What does 750 mean on gold?
It means 75% pure gold, which is 18 karat. 585 is 14 karat and 916 is 22 karat.
How do I verify a HUID?
Enter the 6-digit code in the BIS CARE app’s “Verify HUID” section.
Questions about the hallmark on your piece? Call +91 8733947879 or email care@zarnajewels.com.
