The Bow-Tie Effect in Diamonds - What you NEED to know

An optical phenomenon known as the Bow-Tie Effect is used to describe a shadow resembling a bow-tie that can appear across the centre of Elongated Cut Diamonds. Varying in intensity, Bow-ties range from a dark/black undesirable pattern, to a slight shadow, to barely detectable. 

A bow-tie has nothing to do with the internal features of a diamond. It’s all about the CUT and how the symmetry and alignment of angles affects the dispersion of light. A bow-tie is not an inclusion or defect of the internal diamond. Instead it is better described as an Obstruction of light. It is a shadow WITHIN the diamond as the facets improperly disperse the light that enters.

Although it may appear like an internal flaw within the stone, a Bow-Tie is purely a visual characteristic of a diamond. 

Any engagement ring buyer desiring an Elongated Diamond Shape is sure to encounter diamonds with Bow-Ties during their search. Unfortunately, Marquise, Pear and Oval shaped diamonds are susceptible to this effect due to their elongated proportions.

Bow-ties in diamonds can appear in an assortment of patterns and intensities depending on their unique proportions and faceting arrangements. Pictured above are five examples of how a prominent diamond bow-tie may appear in the Oval Cut shape.

What causes the Bow-Tie effect?

With any Fancy-Cut Diamond shapes that are asymmetrical it requires great skill for a Diamond Cutter to create ideal refraction and polish with their facet arrangement. If the facets are out of alignment they will create these areas of darkness. This asymmetry and poorly polished facets will disrupt the refraction, bouncing light within the stone unevenly. This leads to the appearance of the Bow-Tie shadow - a result of an uneven distribution of light causing light to converge inside the diamond. 

Alternatively, Ideal Diamonds are cut to specific angles with ideal proportions to maximise the refraction of light. This produces their brilliance, sparkle and fire. When a diamond is cut too shallow or too deep, it can result in light loss or light obstruction and cause the formation of the Bow-Tie shadow. With a prominent Bow-Tie Diamond, the light becomes trapped inside the stone or leaks out from the base. To put it simply, a very dark bow-tie is a direct reflection of a Poorly Cut and Poorly Polished Diamond.

Elongated Shape Diamonds (Oval, Pear, Marquise, Radiant, Elongated Cushion) should ideally reflect light through the entirety of its crown/table to sparkle vividly. Diamond facets behave like mirrors, so the brightest stones bounce all of their absorbed light from their pavilions(base) out of the top of the stone. When their facets are perfectly polished they allow the diamond to absorb and refract the maximum amount of light as they are the clearest and most transparent diamonds. This creates that intense sparkle that everyone finds so appealing and what diamonds are renowned for.

As we mentioned in the beginning, the Bow-Tie effect can vary from quite faint all the way to casting a large dark belt across the diamond. People tend to be looking for a bow-tie less prominent, as having a shadow cast a dark spot isn’t exactly the diamond of dreams. Anything that dims the sparkle will change the entire impression of the diamond.

This is why cutting diamonds demands precision and foresight. Skilled diamond cutters plan the external proportions whilst carefully cutting and polishing every facet to emphasize their true beauty. A Diamond cutter holds a tremendous amount of responsibility around the light performance of a diamond and whether it will produce the Bow-Tie Effect. Light should be evenly distributed and refracted throughout the stone for a bright and white sparkle. The arrangement of facets and their polish of a diamond will determine how bright and beautifully a diamond will sparkle.  Any proficient Diamond Cutter will minimise the Bow-Tie effect with their precision to properly diffuse the light optimally to enhance the diamond.


As pictured you can see the the comparison between the elongated diamonds that feature more prominent bow-ties. It is clear how much whiter and brighter an ideal cut diamond appears.

Should you buy a Diamond with a Bow-Tie?

Bow-ties aren’t the end of the world if they’re more subtle like a faint shadow. Also remember, what’s deemed to hinder the appearance of the stone and be quite noticeable to one person may not be to another. But we do recommend avoiding bold Bow-Ties with heavy darkened areas running across the width of the top of the diamond. These type of Bow-ties that darken the majority of the stone and end up looking dull and overcast. By minimising this effect, the brighter your diamond will look, the bigger it will appear and more valuable it will be. The most appealing Elongated Diamonds possess no or less prominent bow-ties.

If you want a diamond that appears bright and sparkly and phenomenal optical qualities for the biggest wow factor we recommend prioritising diamonds with excellent cut grades. They are cut and crafted to maximise brilliance and minimise the bow-tie effect. You can have a flawless diamond, but if it has a poor cut it will subtract from its overall beauty. Never neglect the impact of the CUT of the diamond.

How do I know if the Diamond has a Bow-Tie?

Diamond certificates will provide valuable information about a diamond’s CUT including their symmetry and polish, but tend to lack any information about whether or not a diamond will exhibit a Bow-Tie. This integral information is a key aspect behind a flattering diamond.

For anyone seeking diamonds we encourage them to view the diamond in person. This way you can watch how it interacts with light and discover if any distinct shadows become visible at certain angles. Otherwise you may risk buying a less than desirable diamond. A black distinct bow-tie is not a quality of a spectacular diamond. It darkens the overall diamond, casting a large bowtie shadow across the entire stone and diminishes its sparkle.

Without a visual inspection you’re relying solely on the information provided through a selection of certificates and online videos which won’t always show the bow-tie effect. There are no guarantees that the diamond won’t possess a level of the bow-tie quality. Depending on the angle you’re viewing, a Bow-Tie may not always be noticeable even in a video, and you won’t find it disclosed on a diamond report.

Not every Diamond Shape is threatened by the bow-tie effect. For all of our Round Brilliant Cut Diamond lovers, bowties doesn’t pose a problem. Any diamonds symmetrical in their proportions and have a 1:1 Ratio (Round, Princess, Cushion) cannot produce a bowtie effect.

Conclusion

Coveted diamonds are those that reflect and refract light in countless directions to create a beautiful spectacle. So any feature that interferes with a diamond’s brilliance or impedes on how they reflect light is less than desirable. Brilliant, Bright, White & Sparkly are all things we strive for with diamonds. So the Bow-Tie effect is a feature to minimise as much as possible so it has little impact on the diamond’s appearance for an appealing stone.

Their dark patterning can truly bring down and distract from an otherwise beautiful stone. Diamonds are renowned for their breathtaking sparkle and their symphony of facets reflecting and refracting light in mesmerising ways. So we recommend to steer clear of anything that is obstructing or detracting from this beautiful scinillation, as sparkle and brightness is all integral part of a diamond’s true appeal.

At Janai, our consultants will be sure to guide you in selecting a suitable diamond without dark shadows within the stone. Our expert team has the ability to discern these features and understand the intricacies of Diamond Cutting that may not otherwise be evident. Our consultants are trained to recognise whether or not a diamond will exhibit the bow-tie effect (as they are an unlisted characteristic of a diamonds grading). Our team is sourcing and searching for the most beautiful and bright diamonds for our clients every single day.

If you would like to visit our diamond experts to discover your perfect Elongated Fancy-Cut Shaped Diamond - Fill out your details below to request your consultation with our specialist team. For a Diamond Engagement ring that will shining brightly for years to come. 

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