Why Moissanite Passes Diamond Tester Checks | Moissanite vs Diamond Explained
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Can moissanite really pass a diamond tester? Yes—and it’s not just a fluke. This fascinating fact has turned heads in the jewellery world and is one of the many reasons moissanite is rising in popularity. Known for its brilliance, durability, and ethical appeal, moissanite is more than a look-alike—it’s a standout gemstone in its own right.
In this guide, we’ll explain exactly why moissanite can trigger a positive result on a diamond tester, how the science behind it works, and what it means for everyday buyers. We'll also explore the key differences between moissanite and diamonds, so you can make a confident, informed choice—whether you're shopping for yourself or a meaningful gift.
What Is a Diamond Tester and How Does It Work?
A diamond tester is a handheld electronic device used by jewellers and gemologists to determine whether a gemstone is a real diamond. It works by measuring thermal conductivity—how quickly heat passes through the stone.
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Diamonds conduct heat extremely well.
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Imitation stones like cubic zirconia or glass do not.
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When the device touches the stone, it detects heat transfer and gives a result—usually a beep or a light indicator.
Most standard diamond testers rely solely on thermal conductivity, which is why moissanite can sometimes fool them.
Why Moissanite Passes Diamond Tester Checks
Moissanite is not just a diamond lookalike—it’s a distinct gemstone made of silicon carbide. One of its most diamond-like qualities is its high thermal conductivity, which is very close to that of a real diamond.
Because of this, moissanite can trigger a "pass" result on a thermal-based diamond tester. In most cases, the device reads the stone as a diamond because it cannot differentiate the slight variation in heat transfer.
This is well-documented across jewellery education resources such as GIA’s diamond testing guide and other educational sources, thermal conductivity alone is not sufficient to distinguish all gemstones. That’s why modern testing often involves dual testers, which measure both thermal and electrical conductivity.
Moissanite vs Diamond: A Detailed Comparison
To understand why moissanite performs so similarly on a diamond tester, let’s compare their core properties:
| Property | Diamond | Moissanite |
|---|---|---|
| Thermal Conductivity | Very High | High (nearly identical) |
| Brilliance (Sparkle) | High | Higher (more fire and rainbow flashes) |
| Hardness (Mohs Scale) | 10 | 9.25 |
| Clarity | Natural inclusions common | Typically flawless (lab-created) |
| Cost | $$$$ | $$ |
| Ethical Sourcing | Often mined | Usually lab-grown |
| Environmental Impact | High (mining) | Low (sustainable production) |
When a diamond tester shows "diamond" for moissanite, it’s reflecting just one part of the picture—thermal performance. In every other respect, moissanite continues to hold its own as a durable, sparkling, and sustainable alternative.
Is Moissanite a Fake Diamond?
Not at all. Moissanite is a real gemstone in its own right—chemically, optically, and structurally different from a diamond.
Originally discovered in a meteor crater, moissanite is now lab-grown, making it both environmentally friendly and ethically sourced. It offers:
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Eco-conscious production (no mining)
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Brilliant sparkle (even more fire than diamond)
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Durability for daily wear
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Significant savings for similar visual appeal
Calling moissanite a "fake diamond" overlooks its unique qualities and value. It’s not a knockoff—it’s a modern choice for buyers who value beauty and ethics.
How Professionals Tell the Difference
While a basic diamond tester may pass moissanite as diamond, professional jewellers use more advanced tools to distinguish between the two.
Some of the methods include:
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Dual testers – These measure both thermal and electrical conductivity. Moissanite conducts electricity differently than diamond, revealing its true identity.
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Visual inspection – Trained eyes may notice:
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Slightly more rainbow-like flashes in moissanite (called "fire")
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Different facet patterns under magnification.
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Branded origin – Some moissanite jewellery uses premium branded stones like Forever One or Supernova Moissanite, which are known for high quality and traceability.
Why It’s a Good Thing
Rather than being a drawback, the fact that moissanite can pass a diamond tester is a testament to its quality. It means you're wearing a gemstone with properties nearly indistinguishable from diamond—at a fraction of the cost.
Whether you're investing in moissanite for yourself or gifting it to someone special, you’re choosing:
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Visual impact that rivals diamonds
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High durability for everyday wear
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Ethical and eco-friendly production
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Greater affordability without sacrificing style
Moissanite in DAPR Jewellery
At DAPR, we use D-colour moissanite—the highest grade available—in many of our most-loved designs. You’ll find it in many of our most-loved pieces, including our Everyday Moissanite Earrings, Sentimental Moissanite Necklace, and minimalist engagement rings.
Conclusion: Moissanite Is Brilliant in Every Way
Moissanite’s ability to pass a diamond tester isn’t just a technical fact—it’s a reflection of its brilliance and quality. With a similar look and feel to diamond, yet lower in cost and greater in sustainability, moissanite is the smart choice for the modern jewellery lover.
Whether you’re browsing for a gift or shopping for yourself, explore the world of moissanite and discover jewellery that shines with purpose.