How to Check Gold Purity: BIS Hallmark and HUID Explained

Hallmarking is the single most useful protection a gold buyer in India has. It is an independent check, done by a Bureau of Indian Standards (BIS) recognised centre, that the piece contains the purity the jeweller says it does.

What a hallmark shows

A BIS hallmark on gold jewellery carries three things:

• The BIS logo, showing the piece was tested at a recognised centre.
• The purity grade, such as 22K916 or 18K750. The number is the fineness: 916 means 91.6% gold.
• A HUID, short for Hallmark Unique Identification, a six-character alphanumeric code that is unique to that piece.

Why the HUID matters

Older hallmarks were stamped on the piece and could in principle be misused. The HUID is registered in a central database, so each hallmarked item can be traced to the centre that tested it and the jeweller who sent it. That makes it much harder to pass off an unmarked piece as a hallmarked one.

How to check before you buy

1. Look for all three marks. Use the magnifying glass the jeweller should keep at the counter. The marks are tiny.
2. Match the karat to the invoice. A 22K piece should say 916 and your bill should say 22K, with the HUID listed against the item.
3. Verify the HUID. BIS offers a verification feature in its BIS Care app where you can enter the HUID and see the details of the piece. The app and its features may change, so check the BIS website for the current method.
4. Ask about unhallmarked items. Some very small or special categories can be sold without a hallmark. If a regular piece has no hallmark, ask why.

What if you already own old jewellery?

Older pieces may carry no hallmark or an older style of mark. If you are thinking of selling or exchanging them, a jeweller will test them, and you can also use a BIS recognised hallmarking centre for an independent purity test. There is a small fee.

Other warning signs

Be cautious if a shop quotes a price well below the market rate, refuses to put the karat and weight on the bill, or avoids showing the hallmark. Purity is the thing you cannot judge by eye, so the paperwork matters.

Frequently asked questions