Yes. Moissanite passes older thermal-conductivity diamond testers because it moves heat much like a diamond does. Modern "dual" testers that also measure electrical conductivity correctly identify it as moissanite. So whether moissanite "passes" depends entirely on the type of tester being used.
Why moissanite passes a basic diamond tester
Traditional diamond testers work by measuring thermal conductivity, or how quickly a stone moves heat. Diamonds conduct heat exceptionally well, and moissanite conducts heat at a very similar rate. Because the two are so close on this one property, a basic thermal-only tester cannot tell them apart and will read moissanite as "diamond."
This is why you will sometimes hear that moissanite "fools" a diamond tester. It is not fooling anything. The older tool simply is not designed to catch the difference.
Why modern testers catch it
Newer testers are built specifically to solve this. In addition to thermal conductivity, they measure electrical conductivity. Diamond does not conduct electricity, but moissanite does. A modern dual tester, or a dedicated moissanite tester, uses that difference to flag the stone as moissanite with confidence. So on up-to-date equipment, moissanite is clearly identified for what it is.
What this means for you
Passing a diamond tester does not make moissanite a diamond, and failing a moissanite tester does not make it "fake." Moissanite is its own genuine gemstone with its own identity. The tester result just tells you which stone you are holding. If you want to understand how the two stones really compare, see our guides on moissanite vs diamond and moissanite vs CZ.
If you ever want to confirm what you own, a jeweler with a modern combination tester can identify it in seconds. And because moissanite is prized in its own right for its brilliance, durability, and value, there is nothing to hide. It is simply a different, and often more affordable, path to a diamond-level look. Explore our moissanite chains and moissanite stud earrings to see that brilliance in person.
Frequently asked questions
Does moissanite pass a diamond tester?
Yes, on older thermal-conductivity testers, because moissanite conducts heat similarly to diamond. Modern dual testers that also measure electrical conductivity correctly identify it as moissanite.
Why does moissanite read as diamond on some testers?
Basic diamond testers only measure thermal conductivity, and moissanite conducts heat at nearly the same rate as diamond, so the tool cannot distinguish between them.
How can a jeweler tell moissanite from a diamond?
A jeweler uses a modern combination tester that measures electrical conductivity, which moissanite has and diamond does not, to identify the stone instantly.