London Diamond Bourse Favors Synthetic Terminology

(IDEX Online) - The London Diamond Bourse has adopted "synthetic diamond" as its preferred term for man-made diamonds and is encouraging all its UK members to use the terminology as best practice.

The Bourse said existing UK guidance permits "synthetic," "laboratory-grown" and "laboratory-created" as equally acceptable terms. It said "synthetic" is the most technically accurate, historically established and internationally understood of the three.

In an announcement on 2 September, the Bourse said the decision is intended to promote clear, consistent and transparent terminology across the diamond trade. It said "synthetic diamond" distinguishes a manufactured product from a natural diamond without relying on marketing terminology.

Charlotte Rose, president of the London Diamond Bourse, said consumers should be able to distinguish between natural and man-made diamonds. "Clear and unambiguous terminology allows consumers to make a genuinely informed choice," she said.

The decision follows a unanimous vote by affiliated bourses at the World Federation of Diamond Bourses (WFDB) 41st World Diamond Congress in Singapore in July that "Synthetic Diamond" should be the federation's preferred terminology.

The proposal was submitted by past London Diamond Bourse president Alan Cohen, based on work by the CIBJO Diamond Commission, and was presented at the congress by David Troostwyk, chair of the WFDB Trade and Business Committee and vice president of the London Diamond Bourse.

Troostwyk said the industry had been avoiding a necessary discussion about terminology. "Synthetic diamond is technically accurate, historically accurate and internationally understood," he said, adding that "consumer clarity is and should be paramount."

The Bourse said France requires man-made stones to be described as "diamants synthetiques" and prohibits terms including "created," "grown," "real," "precious" and "true" in their description. It said a request considered by France's Ministry of the Economy and Finance in October 2023 to allow "laboratory-created" as an alternative was rejected.

The Bourse also said Russia introduced rules approved on May 30, 2026, taking effect September 1, requiring jewelry containing man-made stones to be labeled "synthetic." According to the release, the rules reserve "diamond" and its derivatives for natural stones and prohibit terms including "precious," "real," "genuine," "natural" and "eco-friendly" for man-made stones.

The move follows increased regulatory scrutiny of the marketing of man-made diamonds in Britain. In May 2026, the Advertising Standards Authority upheld complaints against two retailers over advertisements that presented man-made stones as diamonds without adequate qualification, with the London Diamond Bourse and Natural Diamond Council among the parties that brought one case to the regulator.

The Bourse said its position has no legal force and does not change UK law. It is a voluntary trade-body position on preferred terminology, and the Bourse said it will use "synthetic diamond" in its own publications, member communications and public statements with immediate effect.

The London Diamond Bourse is a members' organization for diamond and jewelry professionals in London and a member of the WFDB. It provides industry services including trading facilities, education and industry guidance.