10 Fascinating Facts About What KDM Gold Means for Jewellers

Ask a senior karigar in Bowbazar, Domjur or the goldsmith lanes of Bishnupur what KDM meant to them, and you will hear a story about the workbench, not the showroom. Customers came to see the three letters as a badge of purity. For the people who actually made the ornaments, KDM was a technical fix, and it came with a hidden health cost that eventually pushed the whole trade in a new direction.

The ten facts below explain what KDM gold means from the jeweller's side of the counter: why it was used, why it disappeared, and what it means today for shops and households from Durgapur and Asansol to Bankura, Panagarh and Budbud that still hold KDM-era ornaments.

Fact 1: KDM Is a Solder, Not a Grade of Gold

KDM is how the trade wrote cadmium (Cd). It names the metal mixed into the solder that joins parts of an ornament: the links of a chain, the hook of an earring, the seam of a hollow bangle. It says nothing about how much gold the ornament contains. A KDM piece could be 22K, a little under 22K, or occasionally well below it. Only an assay can tell.

Fact 2: It Solved the Oldest Problem at the Workbench

Solder has to melt at a lower temperature than the metal it joins, or the whole ornament would slump under the flame. Traditional gold solders reached that lower melting point by adding extra silver and copper, which also lowered their gold content. A chain with hundreds of soldered links could quietly slip under 91.6% overall, even when the wire itself was true 22K.

Cadmium changed that. Mixed with gold at roughly 92:8, it lowered the melting point without diluting the joint. For the first time a karigar could solder an intricate 22K piece and have it test close to 22K all the way through.

Fact 3: The Cadmium Mostly Burned Away, and That Was the Point

Cadmium boils at around 767°C, well below gold's melting point of about 1,064°C. When the flame hit the joint, most of the cadmium vaporised and left behind a joint that was almost pure gold alloy. That is why KDM ornaments assayed so well. It is also why the technique was dangerous: the cadmium did not disappear, it went into the air of the workshop.

Fact 4: The Health Cost Fell on the Karigars

Cadmium is classified as a Group 1 human carcinogen, and breathing its fumes is linked to lung and kidney damage. Most Indian jewellery is made in small, poorly ventilated workshops where a karigar may solder for ten hours a day. The documented risk was mainly to the people making the jewellery, through years of breathing fumes, rather than to the people wearing it. That concern, more than anything else, is why the trade turned against cadmium solder.

Fact 5: KDM Became a Sales Stamp Nobody Checked

In the 1990s and 2000s, many shops punched "KDM" or "916 KDM" onto ornaments as a selling point. Customers read it as a promise of purity, but there was no independent body behind the stamp. Any workshop could punch it, so it was only as honest as the shop that used it. This gap between marketing and verification is exactly what BIS hallmarking was built to close.

Fact 6: Hallmarking Took Two Decades to Replace It

BIS hallmarking for gold began as a voluntary scheme in 2000. For about twenty years, hallmarked and KDM-stamped pieces sat side by side in the same display cases. The real turning point came in June 2021, when hallmarking became mandatory for gold jewellery in a large first group of districts, and the six-character HUID (Hallmark Unique Identification) code followed shortly after. A HUID ties each hallmarked article to a record that can be looked up, which a KDM punch never could.

How to read 22K916 and a HUID code on your jewellery →

Fact 7: Cadmium-Free Solders Now Do the Same Job

Metallurgy caught up. Solders formulated to match the karat of the ornament, made with safer alloying metals instead of cadmium, now give joints that assay at the declared purity. For a jeweller this means there is no longer a trade-off between a clean joint and a healthy workshop. It is one reason "KDM" has vanished from reputable counters: the technique it named is simply no longer needed.

Fact 8: A Retail Counter Cannot Sell New Unhallmarked Jewellery

Under the mandatory regime, jewellers registered with BIS must sell gold jewellery hallmarked with purity and HUID, with narrow exemptions such as very light articles under 2 grams. Showing "KDM" as a quality claim in 2026 is therefore a warning sign. Either the shop is selling old stock without re-hallmarking it, or it is relying on a customer's memory of a phrase that no longer means anything official.

Fact 9: Bengal's Karigars Were at the Heart of the KDM Era

Bengali goldsmiths are known across India for fine filigree, hollow work and intricate chains, which are exactly the styles that need the most joints. For decades, karigars from Bengal ran workshops in Mumbai, Chennai and Delhi as well as at home in Kolkata and Howrah. As a result, a large share of the heavy old ornaments held by families in Paschim Bardhaman and Bankura were made during the KDM era: sitahar necklaces, mantasha armlets, patterned chur bangles.

Fact 10: Old KDM Stock Keeps Its Full Gold Value

This is the fact that matters most to anyone holding KDM-era ornaments. Selling does not depend on a stamp or a hallmark. It depends on how much gold is actually in the piece. When a KDM ornament is sold, the buyer measures its purity, weighs its net gold content and pays the live rate on that. Whatever solder was used decades ago does not reduce the price per gram of the gold it joined.

What These Facts Mean at the Counter Today

For jewellers, the KDM story comes down to three habits. First, never describe a new piece as KDM; describe it by its hallmark. Second, when an old KDM ornament comes back for exchange, value it on assay rather than on the stamp, because customers increasingly check. Third, explain the difference to customers plainly. Families remember "KDM" as a word of trust, and a jeweller who explains what replaced it keeps that trust.

For households, it is simpler still. A KDM ornament in your locker is not outdated gold. It is gold made with an outdated technique. Its metal is worth exactly what its purity and weight say it is worth.

Selling KDM-Era Gold in Durgapur and Nearby Towns

Auriksha's City Centre office in Durgapur tests every piece on a German XRF spectrometer in front of you. There is no acid, no scratching and no melting. We then pay the live rate on measured purity and net weight, less a fixed 2% margin and a 1% dust-and-wax deduction. Families bring KDM-era ornaments to us from Asansol, Raniganj and Andal to the west, from Panagarh and Budbud along NH19 to the east, and from Bankura, Barjora and Sonamukhi across the Damodar. Home visits can be arranged if travelling is difficult.

Read next: What KDM gold means for investment, and its market value today →

Read: How to spot authentic KDM-era jewellery vs counterfeits →

Background: KDM, Hallmark and 916 compared side by side →

Service: Old gold buyer in Durgapur (KDM pieces accepted) →

Gold buyer for Panagarh and the NH19 belt →