Mr Big regala l'anello con diamante nero a Carrie Bradshaw in «Sex and the City»
Mr Big regala l'anello con diamante nero a Carrie Bradshaw in «Sex and the City»

How to distinguish between real and synthetic diamond?


Attention: the number of synthetic diamonds is increasing, which are now even produced by De Beers. Do you know how to recognize laboratory-created diamonds? The first thing to know is…  ♦

How do you know if the diamond in your ring is synthetic? Is it possible to find out if a diamond is real or fake? The answer is: it depends. The difference is not visible to the naked eye, but only with sophisticated instruments. Naturally, a diamond is considered fake only if its origin is not declared. Synthetic diamonds, if they are officially declared as such, cannot be considered fake. Lastly, diamond giant De Beers has also entered the scene, producing synthetic diamonds with a laboratory in Great Britain for jewelery under the Lightbox brand.

Orecchini lab-grown di Lightbox
Lab-grown earrings by Lightbox

The misunderstanding between real and synthetic, however, is a problem for traders: in fact, in case of doubt, for large stones traders turn to gemological institutes. But if the certifications are dubious, large jewelers do not use smaller stones, under 1 carat, to avoid the risk of compromising their reputation. Alberto Osimo, diamond wholesaler and president of the Geci (Gemological Education Certification Institute) of one of the main gem laboratories in Italy, stated this some time ago: «Currently there is only one machine, the Diamond view, produced by Dtc, the Diamond trading company, able to carry out this analysis, which however takes ten minutes and is uneconomical in the case of diamonds of one hundredth of a carat. In fact, it is not convenient to certify and check a stone worth just a few euros when the procedure could cost up to 80 euros per piece.” However, other systems subsequently proposed to analyze diamonds also require long and expensive procedures.
By Ethereal Green Diamond, 34,59 ct. Photo: Johnny (Chak Wan) Leung
By Ethereal Green Diamond, 34,59 ct. Lab-grown diamond. Photo: Johnny (Chak Wan) Leung

A partial solution to the problem comes from another machine created by the Swiss institute Ssef and capable of analyzing even 4 thousand stones in a single hour. So everything is fine? In part: the device only identifies the molecular structure of the object, i.e. it divides them according to type. And, fortunately, only one of these categories is artificially replicable. In short: a synthetic diamond can only be identified with expensive machines and complicated procedures.
Expertise in un laboratorio Tiffany
Expertise in a Tiffany laboratory

But it’s not just synthetic diamonds. Alongside the natural diamond, there are laboratory-created stones on the market, such as cubic zirconia and synthetic moissanite. Which are certified and sold as extremely cheaper alternatives to diamonds which are the result of the thousand-year-old work of the earth.

So, how do you know if your diamond is real or fake?

1 A real diamond is certified. Therefore, a diamond jewel must also have the certificate attesting its purity, color and carats.

2 You can purchase a device to test yourself. A device such as the Professional Diamond Selector I. It is a probe or thermal conductivity meter and can be found on sale on Amazon for a few dollars, serves to distinguish real diamonds from other simulated stones. For example, it finds out whether the stone is, in fact, a crystal or a cubic zirconia. However, he will not be able to find out if the diamond was created in a laboratory.

3 Other tests that you can do at home: drop the diamond into a glass full of water (but this presupposes that it is separated from the jewel). If the gemstone sinks it is a real diamond. If it floats on the surface of the water or just below it, it is false.

4 Breath test: fog the diamond with your breath, as if cleaning the lenses of your glasses. If the water vapor dissolves immediately from the surface, the diamond is more likely to be authentic. Needless to say, it’s a very crude method…

5 Take a magnifying glass. If you see the tiny abbreviation CZ on the stone it means that it is cubic zirconia.

6 A test for strong hearts: heat your diamond on a flame for 40 seconds. Then throw it in a glass of cold water: if it’s real it won’t break. But if it’s a crystal…  We don’t recommend it, if you want to try it’s your risk.

Controllo del reattore al plasma CVD che produce diamanti ​​in laboratorio
Control of CVD plasma reactor producing diamonds in De Beers laboratory


  1. Grazie i consigli sono molto utili per chi si accinge a questo mondo io cerco di arrotondare comprando anelli a prezzo per montarli con pietre di valore così posso recuperare qualche euro in più ho acquistato la sonda bilancia provaoro e cquantaltrocquantaltro ma l’ esperienza non si paga.

  2. Tengo una piedra que se asemeja a diamante negro o un trozo de meteorito como puedo averiguar por fotos e imagen y características se a parece harto pero igual me gustaría tener seguridad para venderla gracias.

    • Querido David, para una opinión experta sobre un mineral es necesario observarlo de cerca, una foto no es suficiente. Le recomendamos que contacte a un experto en gemología en su ciudad.

  3. Attenzione perché l’ultima prova elencata, relativa allo shock termico, può rovinare internamente anche un diamante vero! Se la purezza del diamante, infatti, non è tale da presentare assenza di inclusioni, nonostante la sua autenticità lo shock termico potrebbe rovinarne la struttura cristallina, lasciando intatta la gemma ma degradando internamente il suo grado di purezza, arrivando anche a rovinare l’effetto visivo (riflessione e rifrazione del taglio realizzato). Dipende da come sono posizionate le inclusioni e da cosa siano composte, è un test che non ha senso fare in gioielleria. Molto meglio rivolgersi a professionisti seri e non direttamente coinvolti nell’acquisto.

    • Siamo perfettamente d’accordo, meglio ribadire: per non fare danni e avere un responso sicuro meglio rivolgersi a un esperto (è detto anche nell’articolo). Le prove descritte non sono una garanzia e possono anche diventare pericolose. In ogni caso, grazie per il tuo contributo!

  4. tengo una piedra encotrada pesa 36 gramos esta entre amarillas marron esta como aceitosa muy dura y muy fina el engrasamiento no se kita con nada meneandola se be crista kisiera saber lo k es normal no es

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