The Diamond Producers Association (DPA) and Signet Jewelers have published the first results of their program designed to measure how well lab-grown diamond detectors actually work.

The first phase of the Assure Program tested 11 lab-grown diamond detectors and screeners, according to standards developed by third-party test agency UL and a technical committee of leading scientists and gemmologist.

Each machine looked at a deliberately challenging sample (including natural diamonds, lab-grown diamonds, and, if applicable, diamond simulants) designed to provide an indication of their relative performance.


All results are published in the Assure Directory, which can be viewed HERE.

The DPA are pleased with the first batch of results, which revealed every device but one registered false positives, meaning they either called a natural stone synthetic or referred it for further testing, and two of the machines misidentified some lab-growns as natural.

Diamond Producers Association chief executive officer, Jean-Marc Lieberherr, shares: “Trade participants have a shared responsibility to disclose the nature of the product they are selling to protect the end consumer. Through the Assure Program we will support the diamond trade, from independent jewellery retailers to large diamond manufacturers, to make informed decisions on how to ensure that undisclosed laboratory grown diamonds do not enter their natural diamond supply chain. The Assure test results should be considered along guidelines formulated by the Responsible Jewellery Council.”

Through the Assure Directory trade participants can access objective and third party verified information on the relative performance of diamond verification instruments and guidance on how to ensure that their business is protected from undisclosed laboratory grown diamonds.

Responsible Jewellery Council executive director, Andrew Bone, adds: “We welcome this initiative to support the spread of effective diamond verification practices across the pipeline. We will continue to support the DPA and the ASSURE Program in their efforts to enhance consumer confidence in the jewellery industry.”

The Assure directory will be regularly updated as new instruments are submitted to testing or re-testing, and the set of stones included in the sample will evolve continuously to include new synthetics diamonds as they are identified.