How to Check Gold Purity: BIS Hallmark and HUID Explained

What is BIS Hallmarking and why is it mandatory in India?

Hallmarking is the accurate determination and official recording of the proportionate content of precious metal in gold articles. In India, the Bureau of Indian Standards (BIS) operates the national hallmarking scheme under the BIS Act. As per Government of India directives, jewellers can only sell certified hallmarked gold jewellery across notified districts, protecting consumers against substandard alloys and under-caratage.

When purchasing gold ornaments in Ahmedpur, ensuring that every item carries an authentic BIS hallmark protects your hard-earned savings and guarantees that when you later exchange or resell the item, its precious metal content is officially recognised across all Indian jewellers without valuation dispute.

What are the three mandatory stamps on hallmarked gold?

Prior to April 2021, Indian hallmarking used four or five stamps. Under the simplified current standard, genuine hallmarked gold jewellery displays exactly three clear laser-engraved symbols:

• 1. The BIS Logo: A clean equilateral triangular symbol representing the Bureau of Indian Standards.
• 2. Purity and Fineness Grade: Indicates the exact proportion of pure gold in parts per thousand (e.g., 22K916 corresponds to 22 Karat gold containing 91.6% pure gold).
• 3. 6-Digit Alphanumeric HUID: A distinct 6-character identification code (e.g., "AB12CD") uniquely assigned to each individual piece of jewellery at a certified Assaying and Hallmarking Centre (AHC).

What is HUID and how does the 6-digit tracking code work?

HUID stands for Hallmark Unique Identification. It is a unique 6-digit alphanumeric code laser-engraved onto every individual jewellery article at the testing laboratory. Every piece receives its own individual code—meaning two identical-looking bangles will each carry a different HUID.

This code is uploaded to the central BIS database alongside the article type, jeweller registration, purity grade, and gross weight. Because the data is stored in a secure national registry, it creates an unbreakable chain of custody and prevents counterfeit stamps.

How can you verify your jewellery using the official BIS Care App?

Any jewellery buyer in Ahmedpur can self-verify an ornament within 30 seconds using a smartphone:

1. Download the free BIS Care App (available on Android Google Play Store and Apple iOS App Store).
2. Open the app and select the "Verify HUID" feature on the home screen.
3. Enter the 6-digit alphanumeric code engraved on your jewellery piece.
4. Tap Submit. The app will retrieve and display:
   • Jeweller Registration Number
   • Assaying and Hallmarking Centre (AHC) name & address
   • Article Type (e.g., Ring, Necklace, Bangle)
   • Date of hallmarking
   • Purity grade verified by the assay lab

If the information retrieved on screen matches your invoice and physical article, your piece is 100% verified authentic.

What is the difference between 24K, 22K, and 18K gold purity?

Karat (abbreviated K or kt) measures the ratio of pure gold to other strengthening alloys (such as copper, silver, or zinc). Pure gold is 24 Karat (99.9% purity), but in its purest form it is too soft for durable everyday ornaments. The table below illustrates the standard purity grades accepted by BIS:

Where should you look for the hallmark stamp on common jewellery?

Jewellers place laser hallmarks in discrete locations where they will not affect the piece's aesthetics or wear against skin:

• Rings: On the inside shank.
• Necklaces & Chains: On the end loop near the clasp or on a soldered identification tag.
• Bangles & Kadas: On the inner rim.
• Earrings: On the earring post or the back plate of the motif.

Always ask your jeweller to inspect the hallmark through a 10x magnification loupe during purchase before receiving your receipt.