Authenticity Tools
Diamond Tester Limitations: The Moissanite Problem
Basic thermal diamond testers can be fooled by moissanite because it conducts heat similarly to diamond, and no simple handheld tester reliably separates natural from lab-grown diamonds.
How thermal testers work
Most handheld diamond testers measure thermal conductivity, a property in which diamond is exceptional. This works reasonably well to separate diamond from most simulants like cubic zirconia or glass.
The moissanite blind spot
Moissanite has thermal conductivity similar to diamond, so basic thermal testers often misread moissanite as diamond. Dual testers that also check electrical conductivity can usually distinguish the two, but cheaper single-function testers cannot.
Natural vs lab-grown diamond
Crucially, no consumer-grade handheld tester can distinguish a natural diamond from a lab-grown diamond, since both are chemically and physically diamond; that distinction requires laboratory equipment such as spectroscopy used by major gem labs.
Buyer checklist
- ✓ Use a dual (thermal + electrical) tester to rule out moissanite
- ✓ Never rely on a handheld tester to separate natural from lab-grown diamond
- ✓ Request a lab report for authoritative identification of origin
Verification tools & references
Every Riakoob piece arrives certified, insured and covered by our 12-month value promise.
Browse the collection