BIS Hallmark and HUID: How to Read and Check Indian Gold Jewellery

A current BIS hallmark on Indian gold jewellery has three parts: the BIS Standard Mark, the purity in carats and fineness, such as 22K916, and a six-digit alphanumeric HUID. HUID stands for Hallmark Unique Identification. Each hallmarked article gets its own HUID, which you can check with the Verify HUID feature of the BIS Care app.

• That a 916 or 22K stamp without the BIS logo and a HUID was ever tested
• That a HUID belongs to the piece in your hand, unless the article type and purity in BIS Care match it
• Gemstone identity, the making charges, or the price a jeweller will pay when you sell

1. 1Read all three marks under the 10x magnifying glass that BIS-registered jewellers must keep for customers
2. 2Enter the HUID in BIS Care under Verify HUID, then match the article type and purity it returns to the piece
3. 3Check that the invoice gives the net gold weight, the purity in carat and fineness, and the hallmarking charges; if in doubt, have the piece tested at a BIS-recognised hallmarking centre

HUID full form: what the six-digit code is

HUID stands for Hallmark Unique Identification. BIS describes it as a six-digit alphanumeric code that is unique for each hallmarked article and traceable. It can mix letters and digits, and it is laser-marked at the hallmarking centre beside the BIS logo and the purity grade.

HUID marking began on 1 July 2021, and every article hallmarked since then has to carry one. Before that, a BIS hallmark had four marks: the BIS logo, the purity, the mark of the Assaying and Hallmarking Centre, and the jeweller’s identification mark. A piece with the older four-mark hallmark is not a fake. It was hallmarked under the earlier scheme.

Behind each HUID is a BIS record of the jeweller who submitted the article, their registration number, the purity, the type of article, and the hallmarking centre that tested and marked it. That record is what the Verify HUID feature shows.

The three marks in a BIS hallmark

Read the hallmark as a set. BIS lists three required marks on gold jewellery, and the manufacturer or jeweller may add its own mark beside them. A piece that shows only one or two of the three, such as 916 alone, does not carry a complete BIS hallmark.

• BIS Standard Mark: the BIS logo, showing the article was hallmarked under the BIS scheme.
• Purity in carat and fineness: a grade such as 22K916, where 22K is the caratage and 916 is the minimum gold content in parts per thousand.
• HUID: the six-digit alphanumeric code unique to that article.

BIS gold purity grades, from 9K to 24K

The Indian Standard for gold hallmarking, IS 1417, sets the grades. BIS lists seven gold caratages under the current scheme, each with a minimum fineness in parts per thousand, so a 22K916 piece claims at least 91.6 percent gold. Several of the numbers have their own pages here: 375, 585, 750, and 916.

• 9K: 375, or 37.5% gold
• 14K: 585, or 58.5% gold
• 18K: 750, or 75.0% gold
• 20K: 833, or 83.3% gold
• 22K: 916, or 91.6% gold
• 23K: 958, or 95.8% gold
• 24K: 995, or 99.5% gold

How to check a BIS hallmark and HUID number

Start with the piece. Registered jewellers must keep a magnifying glass of at least 10x so customers can check the hallmark, so ask for it and find all three marks. Copy the HUID exactly.

Then open BIS Care, the official BIS app for Android and iOS, and use Verify HUID. For gold, BIS says the result gives the jeweller who had the article hallmarked, their registration number, the purity, the type of article, and the hallmarking centre that tested it. Match those details against what you are holding: a HUID recorded for a ring should not be on a chain, and a 22K916 record should not sit beside an 18K750 stamp.

BIS also records photographs and an automatically captured weight for gold articles hallmarked from 8 June 2026, and says these are available in BIS Care for consumers to check before buying. Older records may not include them.

Finally, read the bill. BIS requires the invoice for hallmarked jewellery to describe each article separately and give its net precious-metal weight, its purity in carat and fineness, and the hallmarking charges. It must also say that you can have the purity verified at any BIS-recognised Assaying and Hallmarking Centre.

Signs of a fake or incomplete hallmark

BIS treats a counterfeit hallmark and the sale of articles with an incomplete hallmark as unfair practices by registered jewellers. Verify HUID confirms a record, not the metal: the record supports the piece in your hand only when its article type, purity, and any photograph or weight agree with it. Stop and check further if you see any of these:

• Gold sold as hallmarked by a registered jeweller after 31 March 2023 with no HUID on it.
• A purity number such as 916 or 22K with no BIS logo and no HUID beside it.
• A HUID that Verify HUID does not confirm, or whose article type or purity does not match the piece.
• A code with more or fewer than six characters.

If the gold is less pure than the hallmark says

Any consumer can have hallmarked or unhallmarked jewellery tested at a BIS-recognised Assaying and Hallmarking Centre for a charge. The centre issues an assay report that identifies the article by its marks.

If hallmarked jewellery is found to be of lower purity than marked, Rule 49 of the BIS Rules, 2018 entitles the buyer to compensation of two times the difference calculated on the shortage of purity for the weight of the article sold, plus the testing charges. Complaints can be made through the BIS Care app, the online complaint portal on the BIS website, or a BIS regional or branch office.

BIS also says a hallmark remains valid for the entire life of the jewellery, and that consumers can sell old hallmarked or unhallmarked jewellery to jewellers.

916 KDM: why 916 alone is not a BIS hallmark

916 is the fineness of 22-karat gold: 916 parts gold per 1,000, or 91.6 percent. Inside a BIS hallmark it is written 22K916. Stamped on its own, 916 is the maker’s or seller’s purity claim, not a tested hallmark. The 916 gold page covers the number itself.

KDM is a jewellery-trade term, not a BIS mark. In the Indian trade it is generally used for gold soldered with a cadmium-bearing alloy. Cadmium in solder is a recognised source of exposure in jewellery making, and a study of small jewellery workshops in India found far higher urinary cadmium and markedly lower lung function among exposed workers.

BIS keeps these older stamps out of the hallmark. Its guidelines for registered jewellers say that jewellery bearing any marking, including KDM or a fineness or caratage, must not be sent to a hallmarking centre for hallmarking. A 916 KDM stamp is therefore a trade claim about purity and construction, not evidence that anyone assayed the piece.

BIS also explains why solder matters: Indian jewellery is mostly made of high-caratage gold with numerous soldered joints of lower caratage, and 24-carat plating over lower-caratage articles is common. Both make purity hard to judge from the outside. Before a 916 KDM piece is sold or exchanged, have it tested at a BIS-recognised centre. The guide on how to tell if gold is real explains what home checks can and cannot show.

Exemptions, small pieces, and silver hallmarks

Mandatory hallmarking of gold jewellery began on 23 June 2021 in 256 districts and has since been extended to more districts in phases. Its exemptions include gold articles under 2 grams, kundan, polki, and jadau jewellery, and specified export, exhibition, medical, dental, and industrial articles, among others. An unhallmarked chain under 2 grams is therefore not automatically suspect, but it carries no tested purity claim either.

Silver hallmarking in India is voluntary, but since 1 September 2025 any silver article that is hallmarked must carry a HUID. A silver hallmark shows the BIS Standard Mark with the word SILVER, the purity grade, and the six-digit HUID, and it can be checked in BIS Care in the same way. The revised silver standard, IS 2112:2025, has grades from 800 to 999, including 925 sterling silver.