How to Identify a Diamond

There are several tricks for telling a real diamond from a fake with the naked eye. They may offer useful clues, raise suspicions or confirm doubts, but bear in mind that none of them allows for a definitive, reliable identification.

How to identify a diamond with the naked eye?

Before exploring how to identify a real diamond, it is worth remembering that this exceptionally hard stone (Mohs scale: 10), with its magnificent brilliance, can only be authenticated through a precious stone appraisal carried out by a professional gemmologist. Alternatively, you may purchase a diamond accompanied by its laboratory certificate.

To identify a diamond with the naked eye, try the light test. This simply involves observing how the stone reflects light. The technique is quite effective at detecting stones known as moissanites (SiC). It is less reliable when it comes to zirconium oxides (ZrO₂), which possess a brilliance and "fire" quite similar to that of diamonds. Fire refers to the dispersion of light into spectral colours, much like a rainbow. In moissanites, this fire is more pronounced than in genuine diamonds.

Fake diamonds are most commonly zirconium oxides — widely used synthetic stones that convincingly mimic the appearance of diamonds, yet cost considerably less.

Although popular, the fog test is the least reliable of all the simple tests one can perform at home to identify a diamond. A 10× loupe is preferable, as it can reveal whether the stone is chipped or scratched — in which case it is not a real diamond. Even though diamonds are extremely hard, avoid trying to scratch glass with a stone.

With a 10× loupe, you should already be able to detect any small inclusions, which are never present in synthetic diamonds but are frequently found in natural ones. The same principle applies when identifying a sapphire.

Generally speaking, even if it does not always allow you to detect everything, of course, a loupe is useful for identifying a precious stone.

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How to identify a rough diamond?

It is extremely difficult to identify a rough diamond from a synthetic diamond, as they closely resemble one another. In truth, it is even more difficult than distinguishing a genuine cut diamond from a fake. Call upon our gemology service in Angers or Paris, and we can help you obtain a certificate, should you be in possession of a genuine diamond.

Good to know, however: an authentic rough diamond is never perfectly symmetrical, unlike certain imitations. A real diamond does not normally float in water, or sinks quickly, whereas fake diamonds are lighter — though this is not always a reliable method.

Discover also: how to identify a ruby.

How to identify a diamond on a ring?

To identify a diamond ring, some people find accompanying paperwork that enables the materials to be identified, most notably the certificate of authenticity. Otherwise, the dispersion of light can sometimes dispel any doubt, as it is truly characteristic of a genuine diamond.

The stone seems to glow from within, with a beautiful light that appears to reflect across every facet and then, depending on the lighting conditions, takes on different aspects.

It is a magnificent phenomenon, almost alive, and this is what makes diamonds such exceptional stones. But to identify a fine diamond — whether set in a ring or unmounted, as opposed to a zirconium or another stone, synthetic or natural — it is better not to rely on first impressions and to seek expert assessment instead.