NAJ Reiterates Position on Diamond Terminology

6 August 2018


Owing to recent publicity from the FTC in the US, the National Association of Jewellers confirms that this does not mean the same terminology will be carried across the Atlantic.

Diamonds will continue to be described as Diamonds in the UK only when they are natural. All synthetic diamonds will be preceded with the words Synthetic, Laboratory-Created or Laboratory-Grown. This is in accordance with the CIBJO Blue Book section 4.3 to which the UK jewellery industry adheres. 

Relevant Section:

4.3. Artificial product clauses 4.3.1. Synthetic diamonds Description

The fact that a synthetic diamond (5.72) is wholly or partially synthetic shall be disclosed (5.26).

Only the term “synthetic”, “laboratory-created” or “laboratory-grown” shall be used to describe synthetic diamonds (5.72). These terms shall not be abbreviated, e.g. “synth. diamond”, “lab-grown diamond” or “lab-created diamond” and shall be equally as conspicuous and immediately precede the word “diamond”.

The English terms laboratory-created diamond or laboratory-grown diamond may be used synonymously with synthetic diamond. Where there is no acceptable local direct translation of the English terms laboratory grown diamond or laboratory created diamond then only the translation of the term synthetic diamond shall be used.

NOTE 1 — The usage of the term “synthetic” whenever used alone in this book also refers to “laboratory-created” or “laboratory grown” these three terms are synonymous.

NOTE 2 — The word “laboratory” refers to the facility which produces the synthetic diamonds. This should not be confused with a gemmological laboratory that is dedicated to the analysis, authentication, identification, classification (grading) of diamonds. Term designed to disguise

Any terms that are designed to disguise the fact that a stone is a synthetic diamond or that mislead the consumer shall not be used. Specifically: The words real, genuine and natural or the term cultured shall not be used to describe any synthetic diamond.

For further information contact NAJ’s representative on CIBJO, C John W Henn FGA DGA  email

Diamond terminology Guide

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