Carat$594 million from China, and a prototype press at IIT Madras
India imported about $594 million of rough lab-grown diamonds from China and Hong Kong in FY2025-26. A 242 crore rupee programme at IIT Madras has now run a prototype HPHT press. Single source.
§1A press that ran.
India has completed successful trials of a domestically designed high-pressure high-temperature diamond press, and grew HPHT rough on it, according to a report published on 24 August by Diamond City, the Gujarati fortnightly that serves the Surat trade. The machine is a prototype built by the India Centre for Lab-Grown Diamond, or InCent-LGD, under the 242 crore rupee research programme awarded to IIT Madras when the finance minister announced it in the 2023 union budget. This paper carries the item single-source and labels it so. The report rests on unnamed industry and technical sources, InCent has made no statement of its own, and this desk found no English-language trade coverage of it at press time. The figures below are the outlet's; the arithmetic on them is this desk's.
The money is the part that scales. India bought roughly $594 million of rough lab-grown diamonds from China and Hong Kong in FY2025-26 on the same report's figures, which it converts to more than 4,900 crore rupees. That implied rate of about 82.5 rupees to the dollar puts the 242 crore rupee programme at close to $29 million, or about 4.9% of a single year's import bill, on this desk's arithmetic and the outlet's own conversion rather than a market rate this desk has verified. A research grant equal to one twentieth of one year's purchases is not a substitution plan. It is a licence to stop paying a licence.
§2The bill it is aimed at.
The next phase is already in motion and it has dates attached. Large components for a full-scale commercial press have been manufactured across units in north India and shipped to IIT Madras for integration, assembly and final testing, and the team is collecting feedstock from around the country to standardise raw material and process parameters. Sources at the Gem and Jewellery Export Promotion Council put the indigenous technology and the raw-material trials in their final stage, with an official announcement of the capability likely in November and the first full-scale press expected complete by December. Every one of those dates is an expectation reported through third parties, not a commitment anyone has published, and this desk prints them as such.
A grant worth one twentieth of a year's imports is not substitution.
§3What HPHT holds that CVD does not.
The gap it addresses is specific. India already holds a commanding share of world production by chemical vapour deposition, the other route to a grown stone, and Surat cuts and polishes more than 90% of the world's diamonds. What it has not held is HPHT press capacity, where China's equipment base and scale have made it the supplier of record, and HPHT rough carries a premium for clarity and colour that CVD material does not automatically match. A cutting industry that owns the polishing end of a supply chain and rents the growing end has one bill it cannot negotiate. That bill is the $594 million.
Treat this as a machine that ran, not an industry that changed. A prototype press making good rough at a research institute is three separate distances from a Surat factory floor: a full-scale build, a yield anyone will underwrite, and a cost per carat that beats a Chinese press already amortised. November and December are the dates to hold this against, and if the announcement comes without a carat figure and a cost, it is a ribbon and not a result. The number worth watching is not the press. It is whether that $594 million import line is smaller in FY2026-27 than it is now.
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