What did that diamond tester actually prove?

Three quick takeaways

What to actually do when you shop

• A positive thermal result tells you about heat response. It does not tell you whether a diamond is natural or lab-grown.
• Some look-alikes can also pass certain thermal testers, so treat a beep as one screen, not an identification.
• Before buying, ask what was tested and check the report.

The tester and diamond footage is AI-generated illustration, and the heat diagram is simplified. No real device reading is shown. The narration uses an AI-generated voice. Captions are shown in the video.

Read the transcript

That beep does not prove your diamond is natural. A basic thermal tester checks how heat moves through a stone. Natural and lab-grown diamonds both conduct heat well, and some look-alikes can also pass certain thermal testers. So a positive result is not a complete identification. Specialized instruments and laboratory testing can investigate origin. Before buying, ask what was tested and check the report. Explore more in the Aydins Jewelry Learning Center.

Sources

• GIA, how to identify laboratory-grown diamonds (FAQ): www.gia.edu/FAQ/gia-faq-analysis-grading-identify-laboratory-grown-diamonds
• Presidium, how diamond testers work: www.presidium.com.sg/blog/diamond-testers
• GIA Gems & Gemology, Winter 1997: synthetic moissanite: gia.edu/gems-gemology/winter-1997-synthetic-moissanite-nassau
• International Gem Society, what common diamond tests mean: www.gemsociety.org/lesson/how-to-spot-a-fake-diamond-what-these-13-tests-really-mean/

Related lessons

Lab-grown diamond vs cubic zirconia · what makes a diamond a diamond.

Three checks before trusting a diamond report · how to match a report to the stone.

From a diamond seed to a finished stone · how lab-grown diamonds are grown.