8 Gemologist Tips to Know if an Emerald is Real

I still remember my first visit to a jeweller's in Bangkok. The old craftsman, with his calloused hands and piercing gaze, showed me two seemingly identical emeralds. "This one is worth €5,000, the other barely €50. Can you tell them apart?" he asked with a mischievous smile. This impromptu lesson changed the way I look at these stones forever.

Emeralds have always seduced us. Their intense, almost mystical green has stood the test of time, retaining its power of attraction. Cleopatra was crazy about them, the maharajas snapped them up, and even today, they are the stuff of dreams. But beware: for every real emerald, how many fakes are on the market?

At Mayuri Paris, we only work with natural emeralds. natural emeraldsmainly from Zambia, traditionally treated with oil. If you prefer other origins such as Colombia or Brazil, we can source them on request.

1. The "garden" - emerald's natural signature

My first instinct when examining an emerald? Get out my 10x magnifying glass and look for what we affectionately call the "garden". These natural inclusions - tiny fractures, tiny needles or trapped crystals - tell the story of the stone's eventful history.

A perfectly clean emerald? Beware! Nature isn't that perfect. I've seen customers disappointed to learn that their flawless "super bargain" was in fact a laboratory imitation.

On the other hand, I've learned to recognize artificial inclusions: bubbles that are too regular or linear structures that betray glass or synthetics.

2. UV reaction - a revealing behavior

One evening, in the workshop of a gemologist friend, we played with illuminating different emeralds with his UV lamp. Surprise: the reactions were completely different depending on their origin!

Colombian emeralds glowed with a slight reddish fluorescence, while those from Zambia remained almost inert. These subtle differences tell us a lot about their chemical composition and place of birth.

Beware, however: some synthetics also react to UV light, but often more intensely or uniformly.

3. The weight that doesn't lie

"Here, weigh these two stones", a Rajasthani trader once told me. The difference was obvious: for the same volume, the natural emerald seemed lighter than the leaded glass imitation.

The density of a real emerald varies between 2.7 and 2.9 g/cm³. This is a valuable clue, especially when you're used to handling these stones. With a small container of water and a precision balance, you can even calculate this density at home.

4. The fog test - simple and effective

I love showing beginners this little trick: blow lightly on the stone to create fog. On real emeralds, the fog disappears quickly, as the thermal conductivity is good.

On some imitations, notably glass, the fog will linger. It's not infallible, but it gives an indication without any special equipment.

5. Hardness - strong but fragile

With a hardness of 7.5 to 8 on the Mohs scale, emerald is paradoxical: hard enough to scratch glass, yet brittle enough to shatter easily. That's why experienced cutters treat it with such care.

I strongly advise against scratch testing - too risky! But knowing that an emerald can be scratched by a sapphire or ruby can be useful in certain situations.

6. Dichroism - when color changes with angle

My first encounter with a dichroscope dates back to my student days. What a revelation! A natural emerald shows a subtle variation in color depending on the angle of observation: from green-yellow to blue-green.

Imitations lack this fascinating characteristic. It's as if the stone were telling you its crystalline story, changing hue before your very eyes.

7. Refractive index - optical signature

True enthusiasts invest in a refractometer. The refractive index of an emerald is between 1.57 and 1.58. I've seen smartphone apps that, with a small accessory, allow you to estimate this index.

A higher index often betrays an imitation glass or synthetic spinel. For me, it has almost become a reflex to check this parameter on important stones.

8. Treatments - the art of improvement

During a trip to Colombia, I visited traditional workshops where emeralds have been immersed in oil baths for generations. This ancestral treatment, which is accepted by the market, improves clarity without denaturing the stone.

On the other hand, some modern treatments with resins or polymers leave me perplexed. These heavy interventions create stones that are too "perfect", too shiny to be honest.

At Mayuri, we prefer natural emeralds with only the traditional oil treatment, never synthetic resins or aggressive processes.

Conclusion: expertise remains irreplaceable

These tests have often saved me, but there's no substitute for the trained eye of a professional. After years of handling these stones, certain details stand out: the way light passes through the stone, its reaction to changes in lighting, its temperature to the touch...

If you're looking for a large emerald, choose jewelers who offer gemological certificates. If in doubt, consult an independent expert or a specialized laboratory.

A genuine emerald tells a story that goes back millions of years. It bears the traces of its eventful formation, and this is precisely what makes it so priceless.