Moissanite is a lab-created gemstone that has become one of the most popular diamond alternatives in modern jewellery. It is prized for two things above all: its brilliance, the white sparkle it throws back under light, and its fire, the rainbow flashes it produces as light moves through it. Because it looks so close to diamond, one question comes up again and again before anyone buys a piece set with it: does moissanite pass a diamond tester? This guide gives the honest answer, including the part many sellers prefer to leave out.
The short answer
Yes. Moissanite passes standard diamond testers. The pen-style testers most jewellers keep on the counter work in one of two ways: most measure thermal conductivity, and some measure how light passes through the stone. Diamond conducts heat exceptionally well, and moissanite's thermal conductivity is very close to diamond's — close enough that a thermal tester reads it as diamond. Light-transmission testers are passed for the same general reason: moissanite behaves enough like diamond under those basic tests that the device cannot separate the two. So if a jeweller touches a pen tester to a moissanite stone, it will pass. That result is real. What it does not mean is that the stone is a diamond, and the difference matters.
Where moissanite shows itself
A basic tester is a screening tool, not a laboratory. On a lab assay — the advanced analysis performed with proper gemmological equipment — moissanite is identified as moissanite, not diamond. Its chemical composition and optical properties are distinct, and a laboratory can tell them apart without difficulty. Any seller who claims moissanite is indistinguishable from diamond under every possible test is misleading you. At Harlem Bling we state this openly, including on our own product pages: our stones will show up as moissanite and not diamond on lab assays. A stone does not need to pretend to be something else to be worth buying — but you deserve to know exactly what you are buying before you pay for it.
Moissanite vs diamond at a glance
Origin. Moissanite is lab-created; diamond is mined from the earth. Fire. Moissanite actually has more fire than diamond — it splits light into stronger rainbow flashes, which is why many people find it more eye-catching. Hardness. Moissanite measures 9.25 on the Mohs scale, against diamond's 10. It is still one of the hardest gemstones in everyday jewellery and more than durable enough for daily wear. Price. Moissanite costs a fraction of the price of a comparable diamond, which is the single biggest reason for its popularity: the same visual impact, set in a quality piece, without the diamond price tag.
Why we sell it
We sell moissanite because the value case is straightforward. Our pieces are set in solid 925 sterling silver — real precious metal through and through, not a thin finish over a cheap base — and many of our moissanite pieces come with a GRA certificate for the stone. Every piece carries our lifetime warranty. And because the stone is lab-created, the pricing stays honest: you are paying for silver, craftsmanship and a genuinely beautiful gemstone, not for rarity theatre. If you want maximum sparkle per pound spent, in a piece built on solid silver, moissanite is the rational choice — as long as it is sold to you as what it is.
That is the whole picture: moissanite passes a diamond tester, it will not pass a laboratory assay as diamond, and it does not need to. If you would like to see how it looks set in solid 925 silver, browse our moissanite collection and compare the pieces for yourself.