CaratTariff arithmetic: zero for natural, eighteen for grown
The US–India interim trade deal will eliminate duty on Indian-cut natural diamonds while lab-growns keep an 18 percent rate — the first time trade policy has priced the two products differently. The pipeline is already repositioning.
Buried in the US–India interim trade agreement is the most consequential sentence written about diamonds this year: cut and polished natural diamonds go to zero duty, down from twenty-five percent, once the deal concludes. Finished jewelry improves from an effective thirty-one percent to twenty-four. Lab-grown diamonds, explicitly excluded from the elimination, settle at eighteen percent. For the first time, a major trade regime prices natural and grown differently at the border.
The mechanics reward reading. Natural diamonds and gemstones cut in India are covered under the agreement's Annex III; jewelry cast in the United States remains duty-free regardless of where its stones were cut and set. That casting loophole is already reshaping production planning — set the Indian-cut stone in an American-cast mounting and the tariff conversation largely disappears.
For Surat and Mumbai, the stakes are existential. India cuts roughly ninety percent of the world's diamonds by volume, and the tariff era had been brutal: the trade watched the US reciprocal rate swing from fifty percent to twenty-five before the deal framework landed. May's numbers show the whiplash — polished exports up three percent to $981.7 million on a twelve percent volume increase (cheaper mix, more stones), while rough imports collapsed forty-two percent to $617.1 million as factories ran down inventory rather than restock into uncertainty.
The zero-versus-eighteen split also lands as an official thumb on the scale of the natural-versus-grown fight. Governments do not write product philosophy into tariff schedules by accident: New Delhi negotiated hardest for the category where India's value-add is craft and heritage, and conceded the one where its factories compete on electricity prices. Combined with Russia's September labeling rules, the regulatory world is converging on treating the two stones as different products.
The desk's view: when the agreement concludes, expect a sharp restocking wave — Belgian polished imports already jumped twenty-nine percent in May positioning for it — and a widening structural cost gap in natural's favor at the US counter. Timing risk is real; the direction is not.