Natural and Synthetic Diamonds – Terminology, what is the state of play?

Marianne Riou

On the occasion of the release, on March 9, of the new CIBJO website on the terminology that should be used for natural and synthetic diamonds, we wanted to take another look at the issue…

How are natural and synthetic diamonds classified?

Diamond terminology depends on the region of the world in which you operate. Depending on whether you are in France or the United States, for example, the officially accepted terms are not the same.

Thus, in France, the legal terminology for defining diamonds depends on French Decree 2000-65 of 01/14/2002. This decree applies as follows:

“- to gemstones formed in naturally occurring deposits;

– synthetic stones, artificial stones and imitations of gemstones;

– organic materials of plant or animal origin, traditionally used in jewelry;

– fine pearls;

– cultured pearls;

– imitations of fine pearls and cultured pearls,”

and this “regardless of their origin, their source and the use for which they are intended.” 

In France, natural diamonds thus meet the classification for the term “diamants” (diamonds) stricto sensu. And man-made diamonds are “diamants synthétiques” (synthetic diamonds). The following terms are excluded from being used to classify synthetic diamonds: “élevé” (created), “cultivé” (grown), “de culture” (grown), “vrai” (real), “précieux” (precious), “fin” (fine), “véritable” (true), “naturel” (natural).

In the USA, the approach is different and there is greater latitude. The Federal Trade Commission accepts the terms “laboratory-grown” and “laboratory-created“. However, it has removed the word “synthetic”* from the list of terms it approves in its Revised Jewelry Guides. It does not prohibit, but actually recommends using the term “grown.” It has also removed the word “natural” from the definition of diamonds. So we understand that the term “diamonds” when used alone describes natural diamonds.

In view of this information and these discussions of words, the usefulness of ISO standards, published by the International Organization for Standardization, is easy to understand. The organization has 165 members, not all of whom have the same “level of influence” but who define work on international standardization and “ISO” strategies, which they can then adopt at a national level. With regard to man-made diamonds, ISO 18323 of 2015 (which was revised in 2020), and rightly entitled “Jewellery — Consumer confidence in the diamond industry” recognizes the terms synthetic diamond“, “laboratory-grown” and “laboratory-created. It is interesting to note that it is presented as specifying that it is “a set of permitted descriptors for the diamond industry and is specifically designed to be understood by the consumer“. And it is of course in the context of our dialog with the consumer that the scope and accuracy of all these terms are so important…

An ISO standard for cut diamonds

In September 2020, an ISO standard, ISO 24016, was published to guide the certification of polished diamonds. In detail, the aim is to specify “the terminology, classification and the methods that are used for the grading and description of single unmounted polished diamonds over 0,25 carat.” The standard therefore allows for an international update of the 4Cs and can serve as a reference for certification laboratories. The goal is clearly to harmonize reports and thus make them easier to understand for consumers.

On March 9, the CIBJO launched a new website, What is a Diamond?, which aims to clarify how to describe and classify diamonds, whether natural or synthetic. It is recommended, for example, not to use the abbreviations “lab-grown” and “lab-created” to name synthetic diamonds. The simple and didactic What is a Diamond? website is intended for both jewelry professionals and consumers. It is based on the CIBJO’s Diamond Blue Book and is intended to be a reference tool. For more information, read the press release published on

Finally, here is the definition of a “diamond”, as recognized by the CIBJO: “A diamond is a mineral consisting essentially of carbon that crystallises in the isometric (cubic) crystal system. A mineral is natural by definition. […] Thus, unambiguously a ‘diamond’ is a natural material and the unqualified term ‘diamond’ can only designate a diamond of natural origin.” 

To (re)read the articles published on our website on this topic and understand the importance of the discussions on terminology:
 ISO sets new global standards for diamond grading (2020)
 New guidelines clarify:‘Diamond’ means ‘Natural’ (2018) 
 The Diamond Industry – Is 2018 shaking up the diamond industry?
 “The LFG can guarantee an analysis of parcels of melee that is 100% reliable”- Olivier Segura, Laboratoire Français de Gemmologie (2016) 

Source Rubel & Ménasché 

* as a reminder, in January 2018, the Antwerp World Diamond Centre (AWDC), the Diamond Producers Association (DPA), the Gem & Jewelry Export Promotion Council (GJEPC), the Israel Diamond Industry (IDI), the International Diamond Manufacturers Association (IDMA), the US Jewelry Council (USJC), the World Diamond Council (WDC) and the World Federation of Diamond Bourses (WFDB) decided on the use of the term “synthetic” to describe man-made diamonds.