Here’s a question that comes up a lot when people start buying moissanite: How do I know if it’s actually real?
It’s a fair question. When you’re buying a stone that looks like a diamond but costs significantly less, it’s natural to wonder whether you’re getting what you paid for — or something even cheaper masquerading as moissanite.
Let me clear up the confusion, explain what tests actually work, and tell you what “real” moissanite even means.
First: What “Fake Moissanite” Actually Means
When people ask if moissanite is real, they usually mean one of three different things:
1. Is it moissanite pretending to be a diamond? Moissanite is not fake diamond. It’s its own gemstone — silicon carbide, originally discovered in a meteorite crater. Calling moissanite “fake” because it’s not diamond is like calling sapphire “fake ruby.” They’re different stones entirely.
2. Is this stone actually moissanite, or is it cubic zirconia (CZ) or glass? This is the legitimate concern. Some sellers mislabel stones, and CZ is much cheaper than moissanite. CZ also doesn’t hold up over time — it clouds, scratches, and loses its sparkle within a year or two of daily wear.
3. Is this moissanite low-quality? There’s a spectrum within moissanite itself: color, clarity, and cut all vary. A D color VVS1 moissanite and a low-grade off-color moissanite are both “real,” but they look and perform very differently.
Most of the tests below are designed to answer question #2 — distinguishing genuine moissanite from cheaper imitations.
Test 1: The Hardness Scratch Test (Conceptual, Not Practical)
Moissanite scores 9.25 on the Mohs hardness scale. Diamond is 10. Cubic zirconia is around 8–8.5. Glass is around 5.5.
This matters because harder materials scratch softer ones — not the other way around. Moissanite won’t scratch from contact with most everyday surfaces. CZ will.
The practical takeaway: if you’ve had a stone for six months and it’s developing scratches on the surface, that’s a red flag. Genuine moissanite holds its polish extremely well.
Test 2: The Diamond Tester — And Why It’s Complicated
You’ve probably heard about thermal conductivity diamond testers. Here’s the issue with moissanite: old-style diamond testers will read moissanite as diamond. This is because moissanite has high thermal conductivity, similar to diamond — much higher than CZ or glass.
So:
- Old thermal testers: Read moissanite as “diamond” ✓
- CZ: Reads as “not diamond” ✓
- Glass: Reads as “not diamond” ✓
This actually helps you rule out cheap fakes. If your stone reads as “diamond” on a thermal tester, it’s not CZ or glass. It’s either diamond or moissanite.
To tell moissanite from diamond specifically, you need a dual tester (also called a moissanite tester or combined diamond/moissanite tester). These test both thermal conductivity and electrical conductivity:
- Diamond: High thermal, low electrical
- Moissanite: High thermal, high electrical
- CZ: Low both
A dual tester will identify moissanite conclusively. They run around $20–$50 on Amazon and are what most jewelry professionals use.
Test 3: The Doubling Effect Under Magnification
This is one of the most reliable visual tests for moissanite specifically, and it’s elegant in its simplicity.
Moissanite has a property called birefringence — it’s doubly refractive. This means light splits as it passes through the stone, causing facets and inclusions to appear doubled when viewed under magnification.
Under a 10x loupe (jeweler’s magnifying glass), look at the facet edges inside the stone. In moissanite, you’ll see slightly doubled lines. In diamond, you won’t.
This test won’t distinguish moissanite from CZ visually, but it will confirm you have a doubly refractive stone rather than something synthetic and cheap.
Test 4: The Fog Test
Breathe on your stone. Fog it up like you’re fogging a mirror.
Moissanite and diamond: The fog clears almost instantly (within 1–2 seconds).
CZ and glass: The fog lingers for several seconds.
This works because moissanite and diamond both disperse heat rapidly. It’s a quick, low-tech way to rule out the cheapest fakes.
One caveat: this test is less reliable in high humidity or if the stone is set and the metal retains warmth differently. It’s a useful first pass, not a definitive answer.
Test 5: The Look Test — Learning What Real Moissanite Looks Like
With practice, you can distinguish moissanite from lower-quality stones visually. There are a few things to look for:
Brilliance: Moissanite has exceptional fire — the rainbow-colored flashes of light when it catches light at an angle. High-quality moissanite looks almost electric. CZ looks brighter under direct light but more “glassy.”
Color: D color (colorless) moissanite is completely white with no warmth. Lower-grade moissanite may have a slight grayish or yellowish tint. CZ often looks slightly too white — almost harsh under light.
Size-to-weight: Moissanite is slightly lighter than diamond of the same size. If you have scales, a 1ct diameter moissanite will weigh about 0.88ct by diamond standards. This won’t help you identify it at home, but jewelers use it.
Test 6: Ask for the GRA Certificate
If you’re buying new moissanite from any reputable seller, a GRA (Gemological Research Association) certificate should come with the stone. This is a documented grading report that includes:
- Carat weight
- Color grade
- Clarity grade
- Cut quality
- Confirmation that the stone is moissanite
A certificate doesn’t guarantee quality beyond what’s written on it, but it does confirm you’re dealing with a seller who stands behind their product. No reputable moissanite retailer sells certified stones that turn out to be CZ.
If a seller can’t or won’t provide documentation, that’s worth noting.
What About “Lab-Created” vs. “Natural” Moissanite?
Here’s something that trips people up: essentially all moissanite jewelry uses lab-created moissanite. Natural moissanite (found in meteorites and rare geological formations) is so scarce it’s not commercially available.
Lab-created moissanite is not inferior or fake. It’s chemically and physically identical to natural moissanite — the same silicon carbide, the same crystal structure, the same hardness. Labs simply replicate the conditions that create it.
This is similar to lab-grown diamonds: lab-created doesn’t mean synthetic in the sense of being a fake. It means it was grown by humans rather than geological processes over millions of years. The stone is the same.
Frequently Asked Questions About Moissanite Authenticity
How can I tell if my moissanite is real without a tester?
The fog test is the easiest at-home method — breathe on the stone and see how quickly it clears. Real moissanite (and diamond) clears within 1–2 seconds; CZ and glass linger. You can also check for the doubling effect by looking at the stone under 10x magnification: moissanite shows slightly doubled facet edges, which is a reliable indicator of birefringence.
Will a regular diamond tester detect moissanite?
Old-style thermal-only diamond testers will read moissanite as “diamond” because both have similar thermal conductivity. This means these testers can’t distinguish between the two. To definitively identify moissanite, you need a dual tester that measures both thermal and electrical conductivity — moissanite conducts electricity, diamond does not.
What’s the difference between moissanite and cubic zirconia (CZ)?
Moissanite (silicon carbide, 9.25 Mohs) is significantly harder and more durable than cubic zirconia (zirconium dioxide, 8–8.5 Mohs). CZ scratches and clouds noticeably within 1–2 years of daily wear. Moissanite maintains its polish and brilliance indefinitely. CZ is also much cheaper. Under a diamond tester, CZ reads as “not diamond” while moissanite reads as “diamond.”
Can a jeweler tell if it’s moissanite?
Yes. Any reputable jeweler with a dual tester (moissanite/diamond tester) can identify moissanite in minutes. Under magnification, the doubling effect (birefringence) is also a tell. Jewelers encounter moissanite regularly and won’t be confused by it.
Is GRA certification the same as GIA certification?
No. GIA (Gemological Institute of America) is the most respected diamond grading lab globally. GRA (Gemological Research Association) specifically grades moissanite and some lab-grown stones. For moissanite purchases, GRA certification is the relevant standard — it documents what you’re buying and confirms the stone’s identity and quality grades.
Does real moissanite sparkle rainbow colors?
Yes — that distinctive rainbow fire (dispersion) is one of moissanite’s defining characteristics. Moissanite has higher dispersion than diamond, meaning it breaks white light into colors more dramatically. Some people love this effect; others find it slightly less “realistic” compared to diamond. Either way, it’s a feature of genuine moissanite, not a defect.
How do I know if the moissanite I bought online is real?
Buy from sellers who include a GRA certificate with each stone and have a clear return policy. Read reviews that specifically mention testing the stone or comparing it to other jewelry. Avoid anonymous marketplace sellers without verifiable history. If you’re uncertain about a purchase, take it to a local jeweler for a quick dual tester check — most will do this for free or a small fee.
So How Do I Know If Mine Is Real?
Here’s the practical summary:
- Dual tester — The most reliable, objective test. A $30 tester will tell you definitively.
- Fog test — Quick and free. Rules out the cheapest fakes.
- Doubling under loupe — Visual confirmation of birefringence.
- GRA certificate — For new purchases, the cleanest answer.
- Wear over time — Genuine moissanite won’t scratch or cloud. If your stone looks different six months in, something is wrong.
A Note on Trust and Where You Buy
Honestly, the best protection against getting a fake is buying from a seller with clear return policies and verifiable reviews. Moissanite from reputable sellers comes documented. The risk of counterfeiting is much higher on marketplace platforms with anonymous sellers than from established jewelry brands.
If you’re ever uncertain about a stone you already own, any local jeweler can test it in minutes with a dual tester. It’s worth the peace of mind.
All Oglowa moissanite earrings and necklaces are D color VVS1, GRA certified, and set in 14K gold. Browse the collection →
