The collapse of the natural diamond trade is the most consequential industrial story unfolding in western India this year, and the listed-equity universe in Mumbai is now telling you a coherent version of it if read across twenty names.

Surat polishes nine of every ten diamonds traded globally. Its export book to the US has fallen by over 60% in the run-up to the India-US interim trade framework of February 7, 2026, from $3.64 billion to $1.45 billion.

The price of a lab-grown diamond is now roughly a quarter of what it was in 2015, and synthetic stones were used in nearly half of the US engagement rings sold in the first eight months of 2025.

Across that backdrop, India’s diamond-related listed companies refract the shock into four distinct cohorts. Each cohort is absorbing a different part of the rupture; the pattern across them tells you more about how the Indian capital market is processing the crisis than any single company filing does on its own.

The Shock The Index Has To Refract

For a hundred years, the diamond business ran on a single architectural idea that scarcity could be manufactured even when the underlying mineral was not particularly scarce.

De Beers mined the stones in southern Africa, sorted them into sights, and released them into a polishing chain that ran through Antwerp, Belgium and, from the 1970s onward, increasingly through Surat in Gujarat, India. Buyers were taught, over generations of advertising, that a diamond was a store of value rather than a piece of carbon.

That price floor has now given way, from a direction the cartel did not control. The Henan province in central China, once an agricultural belt better known for cattle and peppers, produces about half of the world's lab-grown diamonds, with 80% of Chinese output concentrated in a single county, Zhecheng.

Anglo American, a British multinational mining company that holds 85% stake in De Beers, has written down the book value of De Beers in three consecutive years, from $9.2 billion in 2023 to $2.3 billion at the end of 2025.

The diamond miner posted a $511 million underlying loss for the year, and Anglo is trying to sell the business. The Surat Diamond Bourse, opened in 2023 at a cost of approximately $350 million, is now about 95% empty.

The Four Cohorts The Listed Universe Is Refracting Into

The clearest negative exposure sits at the polished-natural-diamond manufacturer-exporter layer. Asian Star Co. Ltd is the most visible listed proxy for the pure Surat polishing-and-export model, with rough in, polished out, and US wholesale on the demand side. Goenka Diamond and Jewels is also in the same category.

The cohort is thinner than it looks, however. Several historically large listed names are no longer functionally tradable: Gitanjali Gems, Winsome Diamonds and Jewellery, Su-Raj Diamond Industries and Shrenuj & Company are variously delisted, suspended, or in resolution.

The fragility of the natural-stone polishing model has been pricing out of the listed cohort for years, leaving the index thinner each cycle. What remains is what is most exposed.

The next cohort is the integrated jewellery exporters with US wholesale books. They include Goldiam International, Renaissance Global, Vaibhav Global and, on a much larger gold base, Rajesh Exports. They feel demand-side compression from the US tariff and from inventory destocking by US retailers, but are partially insulated because they sell finished jewellery rather than loose polished stones.

Goldiam pivoted 30% to 40% of its mix to lab-grown and opened its own LGD retail chain under the ORIGEM brand. Renaissance Global has executed a similar tilt toward LGD-set jewellery in its US wholesale book.

The lab-grown beneficiary cohort is the cleanest geared to the substitution thesis, and the one that deserves the most caution. Senco Gold operates the Sennes LGD luxury sub-brand, which had 12 exclusive outlets by April 2026 with a stated target of 30 by year-end.

Trent launched Pome inside Westside in 2024 and now runs 20 dedicated LGD stores with online distribution layered on. Sky Gold & Diamonds is positioned in the segment, and on the SME platform, Dev Labtech Venture is a pure-play MPCVD manufacturer pursuing both jewellery and industrial applications. The caveat is that Henan's overcapacity is now flowing into LGD pricing as well. The lab-grown winner thesis was cleaner two years ago than it is today.

The structurally cleanest beneficiary in the listed universe is the International Gemmological Institute, which earns roughly 60% of its revenue from LGD certification. As volume migrates from natural to synthetic, IGI captures fee revenue on both sides of the migration and gains from the formalisation of the lab-grown market.

The fourth cohort is the insulated layer. Titan is the largest listed jewellery name. It is more insulated than most because its mix is roughly 80% gold; diamond is 20% to 25% of the studded business. Its beYon lab-grown diamond launch positions Titan to benefit from the shift away from natural stones rather than lose share to it.

Kalyan Jewellers, PC Jeweller and Thangamayil Jewellery sit in similar territory, gold-dominated, modestly diamond-exposed, and mostly domestic retail rather than US wholesale. The Surat-export shock passes them by.

What The Replacement Layer Has To Do

The natural-stone chain will not disappear. There is a luxury buyer for whom origin and rarity matter, and an industrial buyer for whom synthetic stones in semiconductor, optical and abrasive applications are now the primary use case. De Beers has pivoted its lab-grown business out of jewellery and into industrial uses. Botswana, where diamond revenues have fallen by roughly half, is openly diversifying its economy.

India needs to split the trade into two businesses. The luxury natural-stone segment needs origin certification, provenance audit, and a credible scarcity story. The industrial synthetic segment needs scale, integration with end-use industries, and proximity to the fabs and tool-makers that consume the stones. Surat fits neither cleanly. Its polishing skill is a real asset, but it was built around a volume of mid-market natural stones that is not coming back.

The listed equity universe will capture the second of these segments more readily than the first. IGI on certification, Goldiam on the LGD pivot, Trent and Senco on the lab-grown retail experiment, Dev Labtech on the manufacturing side, all sit comfortably inside the existing market structure.

The luxury natural-stone story, and the polishing-cluster restructuring that has to happen alongside it, will play out in private balance sheets, family-firm consolidations, and the credit conversations between Surat's mid-tier polishers and their lenders. The genuine giants of Surat's polishing trade are unlisted. Kiran Gems, Hari Krishna Exports, Shree Ramkrishna Exports, Dharmanandan Diamonds and Laxmi Diamond are family-controlled, privately held, and collectively account for a far larger share of Indian polished output than the listed cohort.

The next two years of this story will play out in two registers at once. The listed cohort will consolidate around the lab-grown economy, with more Sennes and Pome openings, more IGI certification revenue, and more industrial-synthetic capacity coming on stream at Dev Labtech and adjacent names.

The unlisted cluster will go through a quieter wave of consolidations, exits, and forced sales of polishing capacity, none of which will be visible on the screen until one of the family firms eventually crosses into the listed universe through an IPO or a strategic sale. That crossing, when it comes, will be the signal that the rupture has finished refracting through Indian capital markets and the new shape of the trade is ready to price.