As an independent designer, I know that it is crucial for any jewelry lover to be sure that the diamond they are wearing is truly real. Below you will find my personal guide “How to Tell a Real Diamond from a Fake” that I use when selecting and creating my jewelry.
Proper diamond identification can save you both financial and emotional investment. Counterfeit stones can be of lower quality, inconsistent color, insufficient hardness, and lack a certificate of clarity or carat. As a designer, I always make sure that every piece of jewelry contains an authentic stone – and I’m happy to share with you methods for verifying this.
1. Fog test
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How to perform the test: Breathe lightly on the stone to create a fine mist on its surface.
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What I observe:
- With a real diamond, the fog disappears almost instantly (within 1-2 seconds), thanks to its excellent thermal conductivity.
- With a simulant (e.g. glass, cubic zirconia), the fog persists longer (3–5 seconds).
I think this simple home test is a great first step, but it won't provide 100% certainty - that's why I combine it with other methods.
2. Checking optical properties
A. Refraction and glitter
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A genuine diamond stands out with its high "fire" when white light is refracted into color spectra.
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Simulants tend to have less pronounced shimmer and the color of the refraction appears flatter.
B. Observation under a microscope or magnifying glass
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Inclusions (small internal impurities) are common and unique in natural diamonds.
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Simulants most often have a perfectly clean structure without inclusions or have bubbles (air bubbles in the glass).
Personally, when creating my jewelry, I always photograph the stone under a magnifying glass so that I can compare its properties with the certificate.
3. Professional tests and certificates
A. Diamond tester
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Principle: Measures the electrical conductivity or thermal conductivity of a stone.
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What I expect: The tester clearly indicates “diamond” or “other material.”
B. Lab-grown diamonds vs. natural
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Lab-grown diamonds have virtually identical properties to natural ones – they only differ in origin and often in price.
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However, in both cases, you must have a certificate from GIA, IGI or HRD confirming the carat, clarity, color and origin of the stone.
When and from what size are diamonds certified?
Certificates from reputable laboratories (such as GIA, IGI or HRD) are a guarantee for me that the stone I use corresponds to the stated quality parameters - carat, clarity, color and cut quality. GIA issues a full Diamond Grading Report for loose diamonds from 0.15 ct and above and a simplified Diamond Dossier® (with the 4 C's without a detailed inclusion map) also for stones from 0.15 ct to 1.99 ct . Diamonds smaller than 0.15 ct are commonly certified in-house or in smaller laboratories, not as standard at GIA.
4. Price and resource comparison
The prices of natural diamonds vary significantly depending on carat, clarity and color. If you come across diamond jewelry at suspiciously low prices without a certificate, I think it's a clear signal to be cautious. I always look for:
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Average market prices (e.g. according to GIA reports).
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Seller history – a trusted seller lists a transparent price list and provides certificates.
5. Step-by-step procedure summary
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Take the fog test – a quick home orientation test.
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Examine the stone under a magnifying glass – look for inclusions or bubbles.
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Check the sparkle and refraction of light – a real diamond has a strong fiery effect.
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Request a certificate from a reputable laboratory (GIA, IGI, HRD).
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Use a diamond tester at a jeweler or in a laboratory.
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Compare the price to market standards – suspiciously low prices always make me question.
If you are looking for genuine diamond jewelry with a guarantee of quality and a personal approach, check out my signature collection of handmade rings and necklaces. All stones are certified and each piece of jewelry is created with love and precision.
