More than half of engagement rings sold by volume in the United States feature laboratory-grown diamonds, the CIBJO Congress heard.

Retail prices for laboratory-grown diamonds have fallen in recent years, putting pressure on natural diamond prices, Wesley Hunt, chair of CIBJO’s Laboratory-Grown Diamond Committee, told a session of the 2026 CIBJO Congress on its final day, September 7.

In the nomenclature debate, “synthetic” remains the primary term used by consumers, Mr. Hunt said. However, he added that the Laboratory-Grown Diamond Steering Committee had requested the use of one alternative term: “laboratory-grown.”

CIBJO’s focus in the industry debate over terminology is on precise nomenclature, principles, rules and standards, CIBJO President Gaetano Cavalieri said.

Mr. Hunt said CIBJO had received a letter earlier in September from a group of senior industry participants requesting a deferral of any final decision on the nomenclature of laboratory-grown diamonds.

The committee emphasised that laboratory-grown diamonds would continue to form part of consumers’ future choices.

The market is becoming increasingly segregated. France and Russia, for example, allow only the term “synthetic”, while “lab-grown” or “laboratory-grown” is used in the United States and India.

Laboratory-grown diamonds can provide an entry point for consumers who cannot afford natural diamonds, allowing them to move to natural diamonds when their financial circumstances permit, Mr. Hunt said.

He also referred to unsubstantiated sustainability and ethical claims made by new laboratory-grown diamond brands in India.

Under CIBJO’s procedures, any final decision on nomenclature is taken by the CIBJO Board following guidance from Sector A and the CIBJO General Assembly.

The board was scheduled to discuss the nomenclature of laboratory-grown diamonds later on September 7, following guidance from Sector A and the General Assembly.