The Gemological Institute of America’s famed diamond lab has dropped several clients that submitted HPHT-treated gems without notifying the lab they were processed, lab senior vice president Tom Moses told JCK.

Moses said the clients violated the Institute’s client agreement, which requires a company to “disclose to GIA in writing at the time of submission that such Article is synthetic or that it has been treated or processed.”

“We are taking a much stronger approach,” Moses said. “It’s a huge commitment on our side, but one we take seriously to protect the industry. The clients agreed to a specific code of conduct and they are not abiding by it.”

Moses would not provide any names of the dropped companies, but said they were being reported to industry groups like the World Federation of Diamond Bourses.

The GIA lab in December announced it had seen an increase in the number of larger HPHT gems, often undisclosed.

JCK’s report from HPHT treater Suncrest Diamonds can be viewed here.

UPDATE: GIA has a further comment here.

To receive the latest jewelry news and blogs every day in your inbox, subscribe to JCK’s e-newsletter here.

JCK