Will Moissanite Pass a Diamond Tester? The Honest Answer

It is one of the most searched questions about moissanite, so here is the straight answer.

The short answer

On a basic thermal diamond tester, yes: moissanite typically reads as diamond. Those pen-style testers measure heat conductivity, and moissanite conducts heat much like diamond does, which is exactly why it fools them. On a modern multi-tester that also measures electrical conductivity, no: moissanite is identified as moissanite, because it conducts electricity differently to diamond.

Why we tell you this honestly

We are not in the business of passing moissanite off as diamond, and neither should anyone be. Moissanite does not need to pretend. It is a genuine gemstone with its own name, its own remarkable story dating back to Henri Moissan's 1893 discovery, and optical properties that in some ways exceed diamond, including noticeably more fire. The tester question matters for a different reason: knowledge. If a jeweller waves a basic pen tester over your ring and declares it "diamond", you now know exactly what that device can and cannot tell you.

Can people tell by eye?

In everyday life, effectively no. Moissanite's brilliance, whiteness and clarity mean it reads as a stunning white gemstone to everyone who sees it. A trained gemmologist examining the stone closely under magnification can identify moissanite by its distinct optical character, particularly its extra fire and double refraction. Your dinner guests will not be carrying a loupe.

What actually matters

Choose moissanite because of what it is, not what it can pass for: the second hardest gemstone on earth at 9.25 on the Mohs scale, D-colour whiteness and VVS-grade clarity in every Aura stone, guaranteed conflict-free, at a fraction of diamond pricing. Read the full comparison in Moissanite vs Diamond: The Honest Comparison, or explore our moissanite engagement rings.