Some traditional thermal diamond testers can identify moissanite as diamond because both stones conduct heat efficiently. Newer multi-testers may also measure electrical conductivity to distinguish them.

Why tester results vary

Results depend on the device, calibration, stone temperature, contact point, setting, and operator technique. A single handheld test is not a complete gemstone identification.

What can confirm identity

Gemologists may use magnification, optical observations, conductivity testing, spectroscopy, and other tools. Documentation can support identification, but papers should correspond to the actual stone.

Buyer takeaway

A tester that beeps does not prove a stone is diamond, and a failed reading does not automatically prove a stone is fake. Use appropriate testing and qualified evaluation when identity matters.