Understanding Gold Purity: KDM vs BIS Standards

Two terms come up again and again when buying gold in India: KDM and BIS hallmarking. They are not the same thing, and the difference decides whether you get the purity you pay for. This article explains both standards and why BIS hallmarking replaced KDM as the benchmark for gold purity certification in India.

What is KDM Gold?

KDM stands for 'Kadmium,' an alloy of 92% gold and 8% cadmium. The mixture was popular because cadmium melts at a lower temperature than gold, so it was easier to work with when soldering jewelry. The 92% gold content corresponds to 22 karat.

Cadmium, however, is harmful with prolonged exposure: it can cause respiratory issues and kidney damage. Because of this, its use in jewelry making has been largely discontinued and is now banned in many countries, including India.

Traditional gold jewelry pieces that would have been marked with purity standards.

The BIS Hallmarking System

The Bureau of Indian Standards (BIS) introduced the hallmarking system in 2000 to standardize gold purity certification across India. BIS hallmarking is a quality certification that confirms the purity of gold as per international standards. A BIS hallmarked gold item carries several marks:

• BIS Mark: The logo of the Bureau of Indian Standards
• Purity Grade: Indicates the fineness of gold (e.g., 916 for 22 karat, 958 for 23 karat)
• Assay Center's Mark: Identification of the center that tested and certified the gold
• Jeweler's Identification Mark: The unique mark of the jeweler or manufacturer
• Year of Marking: Indicated by a letter code

The most common BIS standard for gold in India is '916,' which indicates 91.6% pure gold or 22 karat. This has replaced the KDM standard and is now the legally recognized certification for gold purity in the country.

Why BIS Hallmarking Matters

BIS hallmarking provides several benefits to consumers:

• Assurance of Purity: It guarantees that the gold meets the specified purity standards
• Consumer Protection: It protects buyers from under-caratage
• Standardization: It makes gold quality uniform across the country
• Resale Value: Hallmarked jewelry typically has better resale value
• Health Safety: Unlike KDM, BIS standards prohibit the use of harmful metals like cadmium

Since June 2021, hallmarking has been mandatory for gold jewelry and artifacts in India. Selling non-hallmarked gold jewelry above 2 grams is illegal.

The BIS 916 hallmark stamped inside a gold bangle — 916 parts per thousand, or 22 karat.

How to Verify BIS Hallmarking

When purchasing gold jewelry, always check for the BIS hallmark. You can verify the authenticity of the hallmark by:

• Examining the jewelry under a magnifying glass to see all the required marks
• Asking for a certificate of authenticity from the jeweler
• Using the BIS Care app to scan the hallmark and verify its authenticity
• Visiting a certified assaying center if you have doubts about the purity

At Swarn Shikhar, all our gold jewelry carries the BIS hallmark, so the purity stamped on the piece is the purity you get. We encourage customers to verify the hallmark on every purchase.

The rule when buying gold today is short: look for the BIS hallmark and verify it with the BIS Care app before you pay. If you own older KDM jewelry from a family collection, bring it to our Chembur store and we will test its purity and answer any hallmarking questions.