The World Jewelry Confederation (CIBJO) will consider revisions to its standards on diamond terminology and grading at its 2025 Congress, scheduled to take place in Paris from 27 to 29 October. The proposals, led by Udi Sheintal, President of CIBJO’s Diamond Commission, address terminology for synthetic diamonds, the use of the 4Cs grading system, and increased disclosure around diamond origins.
The proposed changes come at a time when the natural diamond sector is facing falling demand, reduced production and growing overlap in how natural and synthetic diamonds are described and marketed.
Revisiting Earlier Decisions
At the 2010 CIBJO Congress in Munich, a resolution was adopted allowing the use of the terms “laboratory-grown,” “laboratory-created” and “synthetic” to describe non-natural diamonds. The decision, supported by the International Diamond Manufacturers Association (IDMA) and the World Federation of Diamond Bourses (WFDB), was made in line with the practices of other industry bodies at the time.
Udi Sheintal has said that while the intention was to integrate synthetic producers into a harmonised framework, that outcome has not been realised. Instead, the terminology has, according to Sheintal, contributed to less clear differentiation between natural and synthetic products in the marketplace.
“Our industry is currently undergoing a period of significant transition,” Udi Sheintal, president of CIBJO’s Diamond Commission, said.
The trade is at a “crossroads” amid a fall in demand for the natural product, price drops and lower production, he continued. “In response, many stakeholders are seeking to re-establish clearer boundaries between natural diamonds and synthetic diamonds — a move that I believe is essential to restoring consumer confidence and ensuring the long-term integrity of the natural diamond market,” he commented.
Terminology Reform
CIBJO will consider removing the terms “laboratory-grown” and “laboratory-created” from the list of acceptable alternatives for “synthetic” diamonds in both its Diamond Blue Book and the relevant ISO standards.
Sheintal stated:“Enhance consumer transparency by requiring that all descriptions and marketing of synthetic diamonds reflect the reality of their origin: they are not grown or created in a ‘laboratory,’ but rather are manufactured in industrial facilities through artificial processes. I would suggest that the preferred term ‘laboratory grown’ was always euphemistic, imparting a sense of scientific mysticism.”
“I believe it is both timely and necessary to reflect on our past decisions, acknowledge where we may have erred, and take decisive steps toward a more transparent and responsible future,” he added.
The original 2010 decision was, at the time, intended to extend a framework of cooperation between natural and synthetic sectors, similar to the approach used for coloured gemstones. However, Sheintal has now indicated that many in the synthetic diamond supply chain used the terminology to promote their commercial interests without alignment on shared standards or ethics.
Grading Standards for Synthetic Diamonds
CIBJO is also proposing that the 4Cs grading system—cut, colour, clarity and carat should only apply to natural diamonds. According to Sheintal, the 4Cs were developed to describe naturally formed diamonds and may not reflect the characteristics of synthetic stones, which are created under controlled production conditions.
He said:
“Restrict use of the 4Cs grading system exclusively to natural diamonds. Synthetic diamonds, given their industrial origin, should be subject to a separate grading methodology that reflects their nature as man-made products. This approach has recently been adopted by the Gemological Institute of America (GIA), which announced on August 26 that it would begin using descriptive terms more appropriate for describing the quality of synthetic diamonds, because ‘most fall into a very narrow range of color and clarity.’”
While GIA has moved away from 4Cs grading for synthetic diamonds, other laboratories, including the International Gemological Institute (IGI), continue to grade both natural and synthetic diamonds using the same system.
Impact of US Tariffs on Diamond Supply Chains
Beyond terminology and grading, Sheintal addressed ongoing trade pressures caused by increased tariffs on diamonds imported into the United States. The US government has introduced a series of escalating import duties on diamonds, particularly those originating from India. Tariffs rose from 10 percent to 25 percent earlier in 2025 and reached 50 percent as of late August.
India, which accounts for approximately 90 percent of global polished diamond manufacturing, has been significantly affected. Export volumes to the US have declined, with reported job losses in manufacturing centres such as Surat. Forecasts suggest the country’s diamond sector could see a revenue reduction of up to one-third this year.
“The disruption brought on by the tariff policy is reverberating through the entire global value chain, as supply to the United States, traditionally the industry’s most robust retail destination, has tightened. Rough diamond demand has weakened as manufacturing output slows, and many smaller traders and family-owned firms face existential pressure,” Sheintal said.
He added:
“The immediate effect for American retailers and consumers has been rising prices. Effectively the tariff is a consumption tax, which has increased the end-cost of diamonds, particularly in the mid- to higher-value segment. Retailers report concerns about the upcoming holiday season, with many anticipating weaker sales.”
He continued:
“At the same time, there are opportunities emerging. For certain categories, the higher cost may reinforce the perception of natural diamonds as rare and precious, creating a counter-narrative that could differentiate them from laboratory-grown alternatives. However, this dynamic will not offset the broader contraction in affordability and demand.”
Industry Response and Possible Exemptions
In response to the decline in US-bound exports, Indian exporters and other diamond centres are expanding their reach into markets such as China, the Middle East and Europe. Domestic demand for diamond jewelry in India is also increasing. On the policy front, the World Diamond Council, CIBJO, IDMA and WFDB have increased engagement with US policymakers to highlight the wider implications of the tariff policy on employment, trade and consumer access.
Legal challenges to the tariffs are ongoing in the United States. Meanwhile, a new “Annex III” was added in early September to a US Executive Order, listing minerals including loose natural diamonds as potentially eligible for exemptions or tariff adjustments under future bilateral agreements. India had not signed such an agreement at the time of writing, but negotiations are under way.
“The tariff issue will remain fluid in the coming months,” Sheintal said. “Court rulings in the United States, legislative initiatives in Congress such as the proposed Trade Review Act, and diplomatic discussions between Washington and New Delhi may alter the trajectory.”
He concluded:
“In the meantime, thus, volatility will continue to characterise the marketplace.
But, during these moments of uncertainty, it is vital that the international diamond and jewelry community speaks with a united voice. Our industry has always been global by nature, and actions taken unilaterally in one country reverberate across continents.
I urge all members to remain engaged with the monitoring and advocacy efforts being led by WDC, to share information from their respective markets, and to contribute actively to shaping a collective response.
Together, we must ensure that our trade remains fair, transparent, and sustainable, and that consumers in all markets continue to enjoy access to the beauty and symbolism of diamonds.”
