BIS hallmark and HUID — what the marks on gold jewellery mean

A hallmark is a certificate stamped into the metal. In India the Bureau of Indian Standards (BIS) runs the scheme: an assaying and hallmarking centre tests a piece and marks it, and the marks tell you the purity and let you trace the piece. Here is what to look for and how to check it.

The three marks

Hallmarked gold jewellery carries three marks, laid out together on the piece, usually inside a ring band or on the back of a pendant or clasp (BIS, Hallmarking overview):

1. The BIS logo — the standard mark, a small triangle-and-dot emblem.
2. The purity and fineness grade — the karat and the parts per thousand of gold, written together: 22K916, 18K750, 14K585, 20K833, 23K958 or 24K999. 916 means 916 parts of gold in 1,000, or 91.6% pure.
3. The HUID — a six-character alphanumeric code, unique to that one piece.

Older pieces may carry a different set of marks: the fineness alone, the assaying centre’s mark and the jeweller’s mark. Those were the earlier format; they are still a BIS hallmark, but they cannot be looked up by code.

What the HUID does

The Hallmark Unique Identification code is assigned to each article when it is hallmarked, and the assaying centre records the article against that code. That record is what makes the code useful: you can look the piece up and see what was hallmarked, where and at what purity, instead of taking the stamp on trust.

To check a piece, install the BIS Care app from BIS, open “Verify HUID” and type the six characters. The app returns the jeweller’s registration, the assaying centre and the purity recorded for that code. If the purity on the app differs from the purity on the piece or the bill, or the code is not found, do not buy.

Which jewellery hallmarking covers

BIS lists the gold purities the hallmarking scheme covers — 14, 18, 20, 22, 23 and 24 karat — and the districts where hallmarking of gold jewellery and artefacts is mandatory. Within those districts a jeweller may not sell unhallmarked gold jewellery of a covered purity. Certain articles are exempt by the rules (for example very light pieces, articles meant for export, and some medical and industrial uses); the current list is on the BIS pages.

Silver jewellery and artefacts can also be hallmarked under a separate set of grades, but silver hallmarking is voluntary.

Reading the mark on a real piece

The marks are small. A jeweller’s loupe, or the magnifier in a phone camera, shows them clearly. Check three things:

• the grade on the mark matches the purity on the bill (a bill for 22K with a piece marked 18K750 is the mistake to catch);
• the HUID verifies in the app and the app’s purity agrees with the mark;
• the marks sit on the piece itself, not on a tag or a clasp that could be swapped.

Why it matters when you sell

A hallmarked piece with its bill is the easiest gold to sell or exchange. The buyer can read the purity instead of testing for it, and the weight and purity are documented. Unhallmarked gold is bought at a discount or after a purity test, and the test, not the seller’s word, decides the price. The guide on selling old gold covers how that valuation works.

The hallmark certifies purity, not price. The IBJA rate for the day sets the value of the metal; the making charge and the shop’s margin are on top, as the jeweller’s bill guide explains.