The Question That Goes Viral Every Week on TikTok — and the Answer That Actually Matters
It comes up constantly on social media: someone runs a moissanite ring over a diamond tester and films the result. Sometimes it "passes." Sometimes it doesn't. The comments go wild either way. If you're buying a moissanite engagement ring and you've seen this content, here's the complete, honest breakdown of what's actually happening — and why it doesn't change the value of what you're buying.
How Diamond Testers Work
The most common diamond testers used by jewellers and consumers test thermal conductivity — how quickly heat transfers through the stone. Diamond conducts heat exceptionally well, which is how these testers distinguish diamond from glass or cubic zirconia (both conduct heat poorly).
Moissanite conducts heat similarly to diamond. This is why moissanite frequently registers as diamond on standard thermal testers — not because someone is trying to deceive anyone, but because the physical properties are genuinely similar.
What About Multi-Testers?
More advanced testers combine thermal conductivity with electrical conductivity testing. Moissanite conducts electricity differently from diamond, so a dual-tester will distinguish them. These devices cost significantly more and are used by specialist jewellers and gemologists — not the average person doing a casual test.
A IGI or GRA certificate does what no tester can: it provides independent, laboratory-verified proof of exactly what the stone is, its grade, and who certified it. This is why certification matters far more than any tester result.
Why This Question Is the Wrong Frame
The purpose of a diamond tester is to distinguish genuine gemstones from glass, cubic zirconia, and synthetic imitations. Moissanite is none of those things — it's a legitimate gemstone with its own identity, its own brilliance, and its own certification system (GRA). The question "does it pass a diamond tester" implies moissanite is trying to pretend to be something it's not. It isn't. It's its own stone, and it happens to be exceptional.
Every moissanite in the Heritage & Co. INVICTA and AETERNA collections comes with a GRA certificate — Gemological Research Association certification that independently verifies the stone's identity, colour grade (DEF), clarity (VVS), and authenticity. There's no ambiguity about what the stone is. There doesn't need to be.
What This Means for Your Purchase
Buy a certified stone, keep the certificate, and don't worry about the tester video. Your GRA certificate is documentation that is accepted by insurance valuators, that travels with the ring, and that establishes exactly what you bought. A diamond tester is a tool for distinguishing stones; a certificate is proof of what you have.
If you want a stone that a dual-tester will identify as a diamond — because it is one — our CLARITAS collection offers IGI-certified lab-grown diamonds from R44,995. A diamond in every sense.
Certified Stones. Real Gold. Heritage & Co.
