Gemological Science International (GSI), one of the world’s largest gemological organizations, has identified undisclosed lab-grown diamonds in jewelry set with natural brown diamonds. The discovery comes at a critical time, as the global jewelry trade increasingly promotes off-color natural diamonds, such as brown and champagne hues, as unique, fashionable, and affordable alternatives to traditional colorless stones.

Using advanced instrumentation, including Fourier Transform Infrared Spectroscopy (FTIR), DiamondView imaging, and Raman spectroscopy with liquid nitrogen cooling, GSI gemologists confirmed that several jewelry items contained lab-grown diamonds mixed alongside natural brown stones. The detected colors ranged from near colorless with faint brown modifiers to fancy dark brown.

This finding builds on GSI’s earlier research into colored lab-grown diamonds, which demonstrated that synthetics can mimic a broad spectrum of natural hues. Together, these results highlight the importance of rigorous screening protocols and transparent disclosure practices to protect both industry stakeholders and consumers.

“As the industry embraces natural brown diamonds, it is essential to safeguard their integrity in the marketplace,” said Debbie Azar, President and Co-Founder of GSI. “Our mission is to ensure consumer confidence by applying advanced science to protect retailers, manufacturers, and the trade — and to support the industry’s efforts to promote natural off-color diamonds with trust and transparency.”

To learn more about GSI’s services, education programs, or color stone capabilities, visit
www.gemscience.net.

A Personal Note from GSI…

We’re glad to see that our recent findings have sparked meaningful discussion — that was our goal. However, we’ve also noticed some misunderstanding about why we posted it, so we want to clarify our intent.

There is a major difference between working in a theoretical or semi-theoretical research setting and working in the real jewelry marketplace. Some specialists examine a few carats of melee for high-end watches or evaluate a handful of top-quality rubies and present their findings as broad industry insight. But the day-to-day reality — where GSI operates — looks very different.

We work with real jewelry, the kind that millions of consumers purchase every day, often spending hundreds or thousands of dollars — meaningful amounts for real families. These customers deserve exactly what they’re paying for. They should never receive jewelry where natural diamonds are mixed with undisclosed lab-grown diamonds.

This is where GSI’s role matters. We screen millions of jewelry items, containing tens of millions of diamonds, every year — not a small sample in a controlled lab environment. Our responsibility is to protect consumers and the industry at scale, with real volume, real data, and real consequences.

And to be clear: we did not “discover” brown diamonds yesterday. We have been reporting on these issues for years. While the industry promotes brown diamonds as an alternative to lab-grown, the reality is that these goods face the same risks as white diamonds — undisclosed mixing, inconsistent screening, and misrepresentation.

Before pushing the next trend, the industry must do its homework. Consumers deserve accuracy, transparency, and integrity — and GSI will continue to lead that charge.