Look closely at a piece of gold and you may find tiny numbers, letters or symbols stamped on it. A jewellery piece may show 22K 916 or 18K 750. A gold bar may carry 999 or 999.9. Hallmarked jewellery in India also carries a BIS mark and HUID.
These markings communicate important information about the purity and identification of the gold. However, terms such as gold hallmark, purity stamp and gold assaying do not mean the same thing.
Each has a different role. Knowing the difference makes these markings much easier to read.
Gold purity tells you how much pure gold an article contains.
Pure gold is naturally soft, so jewellery is commonly made by combining gold with other metals. The amount of gold present can be expressed in karat or fineness. Karat measures purity out of 24 parts. Fineness expresses gold purity in parts per thousand.
For example, 22K gold contains 22 parts of gold out of 24. Its corresponding fineness is 916, which means the article contains 91.6% gold.
Bullion can carry more precise fineness markings. For instance, 999.9 represents 99.99% gold. Once you understand these numbers, reading other gold markings becomes simple.
A purity stamp states the karat or fineness of the gold. For example, a 916 marking represents 91.6% gold, while 750 represents 75% gold. The same purity can also be expressed in karat form, such as 22K or 18K. However, the purity number alone should not be treated as a complete hallmark. A 916 stamp tells you the stated fineness of the article. A BIS-hallmarked jewellery piece carries additional markings that identify it within the official hallmarking system. This is the key difference between a purity stamp and a hallmark.
A gold hallmark is an official mark that records the verified purity or fineness of a precious metal article under a recognised hallmarking system. In India, the Bureau of Indian Standards operates the hallmarking scheme for gold and silver. In simple terms, a hallmark does more than display a purity number. It shows that the article has gone through the prescribed hallmarking process and carries the required identification marks. A purity stamp tells you the stated fineness. A hallmark records that purity within an official verification system.
A BIS hallmark on gold jewellery includes three main components:
The BIS logo shows that the jewellery has been hallmarked under the Bureau of Indian Standards hallmarking system.
This states the purity of the gold in both formats. For example:
22K 916 means 22-karat gold with 916 fineness.
18K 750 means 18-karat gold with 750 fineness.
Both values describe the same purity in different ways.
HUID stands for Hallmark Unique Identification. It is a six-digit alphanumeric code unique to each hallmarked article. The code helps identify and trace the jewellery within the hallmarking system. Consumers can also check the HUID through the Verify HUID feature in the BIS Care app.
Together, these three markings help identify and verify a hallmarked jewellery article.
When buying hallmarked jewellery, also check the invoice. It should mention details such as the article description, net precious-metal weight, purity in karat and fineness and hallmarking charges. If there is ever a doubt about purity, consumers can also get the jewellery tested at a BIS-recognised Assaying and Hallmarking Centre on a chargeable basis.
Before the purity of gold can be recorded, it has to be determined. This is where gold assaying comes in. Assaying is the process used to determine the composition and purity of gold. The result establishes the fineness of the metal. The specific testing methods can vary depending on the article and purpose, but the distinction is simple:
Assaying determines purity.
A purity stamp communicates the fineness.
Hallmarking officially records purity under the applicable hallmarking system.
These three ideas are therefore related, but each performs a different function.
Gold bars, coins and jewellery can carry different types of markings.
For example, a gold bar may display details such as purity or fineness, weight, the refiner or mint name, brand mark and product identification information.
A marking such as 999.9 mainly tells you the stated fineness of the bullion. On its own, it should not be treated as proof of a BIS hallmark, as bullion and jewellery follow different marking requirements. The word “hallmark” is sometimes used loosely to describe any stamp appearing on gold. A better approach is to understand what each mark is communicating.
A purity number tells you the fineness. A refiner or brand mark identifies the source. A hallmark forms part of an official verification system. This distinction becomes especially useful when comparing jewellery with gold coins or bars.
Gold markings are most useful when you know what each one represents. MMTC-PAMP offers 24K gold coins and bars across different weights and designs. Its minted gold products are available in 999.9+ purity, with positive weight tolerance on applicable products.
The purity marking tells you the fineness of the gold, while the refining and quality-control processes behind the product establish the purity being stated.
Whether you are buying jewellery or bullion, reading the markings correctly makes it easier to understand exactly what information the gold is carrying.
Yes. Marks on frequently worn jewellery can become less visible due to friction, polishing or regular wear. If the markings are unclear, the gold can be tested for purity.
Hallmarks are generally placed on a small, less visible part of the jewellery, such as the inner side of a ring, clasp area of a chain or back of an ornament.
Yes. Consumers can get hallmarked or unhallmarked jewellery tested at a BIS-recognised Assaying and Hallmarking Centre on a chargeable basis and receive an assay report.
Gold bars and coins may carry serial or identification numbers to help identify and trace the specific product. These numbers are different from purity markings.
Gold purity itself does not reduce simply because the item is old. However, repairs, soldering or additions made over time can affect the overall composition of the article.
While jewellery and bullion such as gold coins and bars are among its most familiar forms, gold also turns up in places that have little to do with ornamentation. It helps electronic connections work, protects equipment in space and appears in everything from eyewear to dentistry.
Gold purity is commonly shown as 24K, 22K, 999 or 999.9. But these numbers cannot be confirmed by looking at the colour, shine or weight of gold. They need to be tested. This testing process is called gold assaying. The result of which helps determine its purity and supports processes such as refining and hallmarking.
Look closely at a piece of gold and you may find tiny numbers, letters or symbols stamped on it. A jewellery piece may show 22K 916 or 18K 750. A gold bar may carry 999 or 999.9. Hallmarked jewellery in India also carries a BIS mark and HUID.