Every reputable diamond jewellery piece in India carries a small stamp that most buyers never look for and almost no one knows how to read.
That stamp is the BIS hallmark. It is the only independent, government-mandated verification that the gold in your jewellery is what the seller claims it is. Without it, the gold purity stated on the price tag is the seller's claim, not a verified fact.
What the Bureau of Indian Standards Is
The Bureau of Indian Standards (BIS) is the national standards body of India, established under the Bureau of Indian Standards Act and functioning under the Ministry of Consumer Affairs. BIS sets and enforces quality standards across numerous product categories, including precious metals.
For gold jewellery, BIS operates a hallmarking scheme through licensed Assaying and Hallmarking Centres (AHCs) across India. From June 23, 2021, the BIS made it mandatory for jewellers above specified thresholds to sell only hallmarked gold jewellery in most Indian districts.
The BIS Hallmark: What the Stamp Actually Says
A BIS hallmarked gold piece carries four elements on the hallmark stamp.
Element 1: The BIS Logo
A triangle-shaped logo with BIS inside, representing the Bureau of Indian Standards. This confirms the piece was hallmarked by a BIS-licensed Assaying and Hallmarking Centre.
Element 2: The Purity Grade
The gold purity is expressed as a fineness number:
14K gold = 585 (58.5 percent pure gold) 18K gold = 750 (75 percent pure gold) 22K gold = 916 (91.6 percent pure gold) 24K gold = 999
If a piece claims to be 18K gold but the hallmark reads 585, it is 14K, not 18K, and the seller is misrepresenting the purity.
Element 3: The HUID (Hallmark Unique Identification Number)
Every hallmarked piece carries a unique six-character alphanumeric HUID. This number is specific to that individual piece and recorded in the BIS database.
The HUID allows any buyer to verify the specific piece using the BIS Care app (available on Android and iOS) or the BIS website. Enter the HUID and the database returns: the AHC that tested it, the date of hallmarking, and the confirmed purity grade.
Element 4: The Assaying Centre Mark
The AHC that tested and hallmarked the piece stamps its own mark. This identifies which licensed centre performed the testing.
How to Check the BIS Hallmark on Your Jewellery
On a ring: look on the inner surface of the band.
On a pendant: look on the back surface of the pendant setting or on the loop through which the chain passes.
On earrings: look on the post between the setting and the butterfly backing.
On bangles and bracelets: look on the inside surface of the bangle or on the clasp of a bracelet.
The hallmark is physically stamped by the AHC and cannot be rubbed off. If you cannot find the hallmark, ask the jeweller to show you specifically where it is stamped.
Verifying the HUID on the BIS Care App
Step 1: Download the BIS Care app from the Google Play Store or Apple App Store.
Step 2: Select the Hallmark Verification option.
Step 3: Enter the six-character HUID from the piece.
Step 4: The app returns the hallmarking record. Confirm that the purity grade and details match what the seller has told you.
If the HUID does not return a result, or if the result does not match the seller's description, contact the BIS consumer helpline (1800-11-4000) and do not complete the purchase.
Why BIS Hallmarking Matters for Diamond Jewellery Specifically
Diamond jewellery buyers often focus entirely on the diamond quality and overlook the gold setting. But the gold in a diamond jewellery piece represents a significant portion of the total value. For a 0.50 carat diamond solitaire ring in 18K gold, the gold setting may represent 25 to 40 percent of the total purchase price.
Without a BIS hallmark, there is no verification that the setting is actually 18K gold rather than 14K or lower. Over a Rs 50,000 purchase, this difference can represent Rs 5,000 to Rs 12,000 in value that the buyer is not receiving.
At Goenka Jewellers, all diamond jewellery is set in BIS hallmarked 14K or 18K gold. The hallmark stamp is present on every piece and the HUID is verifiable through the BIS Care app before and after purchase.
Frequently Asked Questions
Is hallmarking mandatory for all gold jewellery in India?
Mandatory hallmarking currently applies to gold jewellery sold by jewellers registered with BIS in the notified districts above specified inventory thresholds. As of 2026, mandatory hallmarking covers the vast majority of organised jewellery retail across India.
Can a hallmark be faked?
A physical hallmark stamp can be counterfeited, but the HUID system makes this significantly harder because the HUID is unique to the individual piece and recorded in the BIS database. Always verify the HUID on the BIS Care app rather than relying on the visual appearance of the stamp alone.
Does the BIS hallmark guarantee the gold is exactly the stated purity?
The BIS hallmark guarantees the gold meets the tolerance standards for the stated purity grade. The tolerance for 18K gold (750) is plus or minus 3 parts per thousand. This is standard in precious metal testing globally.
What should I do if a jeweller refuses to show me the hallmark?
Ask specifically where the hallmark is stamped and request a magnifying glass to examine it. Under Indian consumer protection law, selling gold jewellery without the required hallmark is a punishable offence. You have the right to inspect the piece before purchasing.
The Bottom Line
The BIS hallmark is not a technicality. It is the only independent verification that the gold you are paying for is the gold you are receiving. The six-character HUID verifiable through the BIS Care app is the consumer's most important protection tool in the Indian gold jewellery market.
Check for it on every piece. Verify the HUID before completing any significant purchase. Buy only from retailers who actively support this verification.
For the complete metal selection guide, read our Gold, White Gold, Rose Gold and Platinum: Complete Metal Guide India 2026. For safe online purchasing guidance, read our How to Buy Diamond Jewellery Online Safely in India: A 10-Point Checklist. Then explore Goenka Jewellers certified lab-grown diamond jewellery.