How to Identify Lab-Grown Diamonds: Differences from Natural Diamonds, Moissanite, and Cubic Zirconia
"Is this a lab-grown diamond? Or a natural one?"
"I'm not sure what the difference is between moissanite and cubic zirconia."
There are several stones that possess a sparkle similar to a diamond, and even for experts, it is not easy to tell them apart based on appearance alone.
In this article, we will break down the differences between lab-grown diamonds, natural diamonds, moissanite, and cubic zirconia, and introduce key points for how to distinguish between them.
Table of Contents
Basic differences between the four stones
First, let's categorize what kind of substance each one is.
- Natural Diamond: Carbon crystals formed naturally in the earth
- Lab-grown Diamond: Carbon crystals created artificially in a laboratory (real, authentic diamonds identical to natural ones)
- Moissanite: A mineral distinct from diamonds, primarily composed of silicon carbide
- Cubic Zirconia (CZ): An artificial imitation stone primarily composed of zirconium oxide
The major difference is that while natural and lab-grown diamonds are "real diamonds," moissanite and CZ are "different stones that resemble diamonds."
How to distinguish them by appearance
Differences in brilliance (fire)
Moissanite has a higher refractive index than diamond, so it tends to exhibit stronger "fire" (rainbow-colored flashes of light). Under outdoor lighting, this rainbow sparkle can sometimes be a clue for identifying moissanite.
Hardness and scratch resistance
Natural and lab-grown diamonds have a Mohs hardness of 10, whereas moissanite is 9.25 and CZ is around 8.5. In jewelry that has been worn for a long time, differences may appear in surface wear and the presence of scratches.
Differences in weight
Even when they look the same size, CZ has a higher specific gravity than diamond, so it may feel slightly heavier when held in the hand. However, this is a point that is difficult to judge without considerable experience.
That said, these differences are extremely difficult to distinguish with the naked eye, so it is recommended to treat them only as a rough guide.
Identification methods used by experts
To identify them with certainty, appraisal using specialized equipment is required.
- Thermal conductivity tester: Diamonds have very high thermal conductivity, which is used to distinguish them from moissanite and CZ (however, because moissanite shows thermal conductivity close to that of a diamond, this alone is insufficient).
- Electrical conductivity tester: Moissanite has electrical conductive properties, and this difference is used to distinguish it from natural and lab-grown diamonds.
- Lab-grown detector: Specialized equipment developed by institutions such as the GIA, which can determine with high precision whether a stone is natural or lab-grown.
Since identification on your own is difficult, choosing products with an appraisal certificate or purchasing from a trusted store is the most reliable way to identify them.
Comparison table
| Item | Natural Diamond | Lab-grown Diamond | Moissanite | Cubic Zirconia |
|---|---|---|---|---|
| Main Component | Carbon | Carbon | Silicon Carbide | Zirconium Oxide |
| Is it a real diamond? | Yes | Yes | No (different mineral) | No (imitation stone) |
| Mohs Hardness | 10 | 10 | 9.25 | Approx. 8.5 |
| Sparkle Characteristics | Elegant white sparkle | Same as natural | Strong rainbow sparkle | Slightly more subdued than diamond |
| Price Range | Expensive | More affordable than natural | Much more affordable than diamond | Very affordable |
Points to check when purchasing
① Presence of an appraisal certificate and the issuing organization
Check if there is an appraisal certificate from a reliable third-party organization such as the GIA or IGI. The certificate contains information about the stone type and quality (4Cs).
② Description in the product details
Make sure the product description clearly states which stone is used, such as "diamond," "lab-grown diamond," or "moissanite."
③ Reliability of the retailer
Choosing a retailer that has physical stores or responds carefully to inquiries will provide peace of mind after your purchase.
For those who want to learn more
If you would like to know more about lab-grown diamonds, please take a look at the following articles as well.
- What are lab-grown diamonds? Explaining the differences, pros, and cons compared to natural diamonds
- Will I regret buying a lab-grown diamond? 5 check points to ensure you don't
- Are lab-grown diamonds suitable for engagement rings? Differences from natural diamonds and how to choose without regrets
Frequently asked questions
Q. Is moissanite a fake diamond?
A. No, moissanite is not a fake; it is a gemstone made from a different mineral called silicon carbide. While it is treated as a substitute for diamond, it is a gemstone with its own independent value.
Q. Can I distinguish between a lab-grown diamond and a natural diamond myself?
A. Identification with the naked eye is almost impossible. Appraisal using specialized equipment is necessary.
Q. Does cubic zirconia deteriorate quickly?
A. You can use it for a long time with proper care, but because its hardness is lower than that of a diamond, its surface tends to get scratched more easily.
Summary
Both natural diamonds and lab-grown diamonds are real diamonds made of carbon. On the other hand, moissanite and cubic zirconia are stones that are different from diamonds, but are chosen as stones that possess a similar sparkle.
Since it is difficult to identify them by appearance alone, the key to enjoying your jewelry with peace of mind is to check for the presence of an appraisal certificate and ensure the reliability of the retailer.
