Gemological Science International (GSI) has identified undisclosed lab-grown diamonds in jewellery set with natural brown diamonds. The discovery comes at a time when off-colour natural diamonds, including brown and champagne hues, are being positioned in the trade as alternatives to colourless stones.
Detection methods and findings
GSI used Fourier Transform Infrared Spectroscopy (FTIR), DiamondView imaging and Raman spectroscopy with liquid nitrogen cooling to analyse the items. Lab-grown diamonds were found mixed with natural brown diamonds, with colours ranging from near colourless with faint brown modifiers to fancy dark brown.
The organisation stated that these findings are consistent with earlier research indicating that lab-grown diamonds can appear similar to various natural diamond colours. This has implications for detection protocols, particularly for stones outside the traditional colourless category.
Emphasis on disclosure
Debbie Azar, President and Co-Founder of GSI, said the discovery highlights the importance of maintaining clear identification practices:
“As the industry embraces natural brown diamonds, it is essential to safeguard their integrity in the marketplace. 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-colour diamonds with trust and transparency.”
Implications for jewellers
The inclusion of undisclosed synthetics in brown diamond jewellery underscores the need for consistent screening, especially as interest in off-colour natural stones grows. Ensuring proper disclosure from suppliers remains a key consideration.
Jewellers dealing in brown and champagne diamonds may need to review their sourcing and verification processes. As synthetics can resemble natural off-colour stones, the use of reliable detection methods and laboratory analysis is important for accurate classification.
Gemological Science International is one of the largest independent gemological organisations, offering services in diamond and gemstone testing, grading and education.
