The World Jewellery Confederation (CIBJO) has recommended “synthetic” as the only acceptable descriptor for non-mined diamonds, rejecting calls from trade leaders to permit the term “laboratory-grown,” the organization said on Monday.

The decision, finalized at the closing session of the 2026 CIBJO Congress, deepens a global divide over gemstone terminology at a time when manufactured stones are rapidly eroding the market share and pricing power of mined gems.

CIBJO’s Laboratory-Grown Diamond Committee, told delegates that “synthetic” remains the primary term recognized by consumers, despite a formal push from the sector’s steering committee to defer the ruling and authorize “laboratory-grown.”

CIBJO’s move aligns with a growing regulatory push in several major markets. France restricted terminology to “synthetic” in 2024, Russia followed suit in June, and the London Diamond Bourse endorsed the single descriptor on Sunday. In May, the African Diamond Producers Association also tightened descriptor rules to shield the natural diamond trade.

In contrast, regulators and retailers in the United States and India have favored consumer-friendly phrases such as “lab-grown” or “laboratory-grown.” The commercial stakes are particularly high in the U.S., where synthetic stones now account for more than half of all engagement ring sales by volume, applying severe downward price pressure on natural rough and polished stones.

CIBJO, which began moving to strike “lab-grown” from its influential Diamond Blue Book standards last year, warned that the diverging legal frameworks are leaving the global market increasingly fragmented.